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Glossary Results

5q- Syndrome (5q Minus Syndrome)

A World Health Organization term for a subtype of MDS that causes refractory (treatment-resistant) anemia. It affects about 20 to 30 percent of patients with MDS. This subtype causes refractory (treatmentresistant) anemia associated with a deletion of the long arm (q) of chromosome 5, designated “del(5q).”

Absolute Neutrophil Count (ANC)

The number of neutrophils (a type of white blood cell that fights infection) that are identified in the blood count.

Acquired Sideroblastic Anemia

See Refractory Anemia With Ring Sideroblasts (RARS).


A major protein in the blood that plays a role in fighting infections and building or repairing muscle tissue. The normal range for albumin is 3.5 to 5.5 g/dL (grams per deciliter). The optimal level is 4 g/dL. Test results can vary slightly between laboratories and may be affected by the method the lab uses to process the blood sample.

Alkylating Agent

A type of chemotherapy used to kill cancer cells by interfering with cancer cell division. Alkylating agents cause side effects because they also interfere with cell division in certain healthy tissues where cell division is frequent, such as the gastrointestinal tract. Cyclophosphamide is one of several types of alkylating agents.

Allogeneic Stem Cell Transplantation (Transplant)

A treatment that uses healthy donor stem cells to restore a patient’s marrow and blood cells. It uses high doses of chemotherapy and sometimes radiation to “turn off” a patient’s immune system so that the donor cells are not rejected. See the free LLS publication, Blood and Marrow Stem Cell Transplantation.


In myeloma, an abnormal protein made by malignant plasma cells. An amyloid deposit develops when parts of the immunoglobulin molecule, referred to as "light chains," deposit in tissues. In the type of amyloid that occurs in myeloma or closely related diseases, organ failure can occur as a result of amyloid deposits in the heart, gastrointestinal tract, kidney, nerves, and other systems.


A health condition that occurs when a person has a low number of red blood cells and therefore a low hemoglobin concentration. When this happens, it is hard for the blood to carry oxygen. People with severe anemia can be pale, weak, tired, and become short of breath.


The creation of new blood vessels, a critical natural process that occurs in the body both in health and in disease. Normally, the body maintains a balance of angiogenesis regulators. In some disease states, the organs involved may lose control over angiogenesis. In these conditions, new blood vessels either grow too much or not enough.

Anthracyclines (Antitumor Antibiotics)

Chemotherapy agents that interact directly with the DNA in the nucleus of cells, thus interfering with cell survival.


Drugs that are used to treat infections caused by bacteria and fungi. Penicillin is one type of antibiotic.


A type of protein created by blood cells when they are invaded by bacteria, viruses, or other harmful things called antigens. Antibodies help the body fight against invaders that make people get sick. Antibodies can also be made in the lab and are used to help find certain types of cancer and in treatment.

Anticoagulant Therapy

Agents used to block blood clotting when abnormal blood clotting is occurring or is at risk of occurring. Heparin may be used because of its immediate action. It must be injected and if long-term treatment is required, is often replaced later by another anticoagulant, warfarin, which can be taken by mouth in pill form.


A foreign substance, mostly a protein, that creates an immune response when it is eaten, inhaled, or comes into contact with the skin or mucous membranes. Examples are bacteria, viruses and allergens. Antigens stimulate plasma cells to produce antibodies

Antiglobulin Test

A laboratory procedure that can identify antibodies on the surface of red cells or platelets. Patients may make antibodies to their own red cells or platelets (auto- or self-directed antibodies). These autoantibodies may lead to anemia or a low platelet count in patients. The antiglobulin test can be used to identify the presence of autoantibodies on blood cells.


See Tumor Suppressor Gene.


A process using a machine to take out needed parts of the donor’s blood and return the unneeded parts to the donor. This process lets certain blood components, including red blood cells, white blood cells and platelets to be removed separately and in large volumes. See Platelet Transfusion.

Aplastic Anemia

A health condition that occurs when your body stops producing enough new blood cells. Any blood cells that the marrow does make are normal, but there are not enough of them. Aplastic anemia can be moderate, severe, or very severe.

Autologous Stem Cell Transplantation

A treatment that uses a patient’s own stem cells to slow the growth of certain blood cancers. See the free LLS publication Blood and Marrow Stem Cell Transplantation.


See Karyotype.


See Autologous Stem Cell Transplantation

B Lymphocyte

One of three specialized lymphocyte types. They produce antibodies in response to any foreign substance, but to bacteria, viruses, and fungi in particular. These lymphocytes are a vital part of the immune system and are important to our defense against infection. Some B lymphocytes mature into plasma cells, which are the principal antibody-producing cells.

Banding of Chromosomes

The staining of chromosomes with dyes that highlight bands or regions on the chromosome. The bands give the chromosomes more specific features, allowing individual distinctions to be made among them. This technique permits more precise identification of chromosomes. . See Fish (Fluorescence In Situ Hybridization).

Baseline testing

Tests that are used to get information before treatment, which will be compared to information in the test results after treatment.


A type of white blood cell present in certain allergic reactions.

BCL-2 Gene Rearrangement

Rearrangements in the BCL-2 gene that occur on B cells. The BCL-2 gene rearrangement is associated with a chromosome translocation t(14;18) (q32;q21) that places BCL-2 (normally on chromosome 18) adjacent to the joining region (JH) of the immunoglobulin heavy chain locus (normally on chromosome 14). The rearrangement results in a high level of expression of the BCL-2 protein. The overexpression of the bcl-2 protein gives cells a survival advantage by inhibiting cell death. Overexpression of the Bcl-2 protein can occur without detection of the BCL-2 gene rearrangement.


A mutant gene that is formed when a piece of chromosome 9 attaches to the end of chromosome 22. The BCR-ABL cancer gene gives the cell instructions to make a protein that leads to CML. BCR-ABL is found in some patients with ALL.

BCR-ABL Tyrosine Kinase Inhibitor

See Tyrosine Kinase Inhibitor.

Bence Jones protein

An abnormal protein made by the malignant plasma (myeloma) cells, which enters the blood and is excreted rapidly in the urine. This protein can cause injury to the kidney or kidney failure when excreted in large amounts. By contrast, normal immunoglobulin is too large to pass through the kidneys in large amounts, so it is present in the blood but usually not in the urine. Bence Jones proteins are also called "immunoglobulin light chains."


Benzene is a widely used chemical formed from both natural and manufacturing processes. It is used to make plastics, detergents, pesticides and other chemical compounds.

Beta 2-microglobulin

B2M is a protein found on the surface of white blood cells. Increased production or destruction of these cells causes B2M levels in the blood to increase. This increase is seen in people with cancers involving white blood cells.


A brownish yellow substance that is produced mainly when the liver breaks down old red cells. It can be measured in a blood sample.

Biomarkers (cancer cell markers)

Chemicals or structures present either on the surface of or within cells or in the serum. They may aid physicians in determining when treatment (and which type of treatment) is needed by identifying disease that will progress more rapidly and/or have a better or worse response to certain treatments. Examples of biomarkers are gene expression, serum protein levels and chromosome abnormalities in cancer cells. No single feature can accurately predict disease progression in a patient; therefore, physicians use a combination of factors to make a diagnosis and a treatment plan.


A procedure to obtain tissue for diagnosis. In many cases, a special needle can be used to obtain the tissue. In some cases, a larger piece of tissue may be surgically removed. The tissue is placed in preservative, stained with dyes, and examined under a microscope by a pathologist.


A class of drugs, including pamidronate and zoledronic acid, which has been helpful in preventing or minimizing bone loss. Bisphosphonates probably act by preventing cells called "osteoclasts" from dissolving bone. In myeloma, bone thinning (osteoporosis) and fracture are major problems.

Blast cells

A young (or immature) type of cell in the bone marrow. In healthy people, blast cells make up 5 percent or less of normally developing marrow cells.

Blood Cell Count

A lab test that measures the number and types of cells in the blood. Often called a “complete blood count” or “CBC.”

Blood Cells

There are three types of blood cells: red blood cells, which carry oxygen; white blood cells, which fight infections; and platelets, which help stop bleeding.

Bone Marrow

A spongy tissue in the hollow central cavity of the bones where blood cells are made. By puberty, the marrow in the spine, ribs, breastbone, hips, shoulders and skull is most active in blood cell formation. In adults, the bones of the hands, feet, legs and arms no longer contain blood-forming marrow—these bones are filled with fat cells. When marrow cells have matured into blood cells, they enter the blood that passes through the marrow and are carried in the bloodstream throughout the body.

Bone Marrow Aspiration

A test to find abnormal marrow cells. The area around the hip bone is numbed and then a special needle is inserted and a marrow sample (fluid) is drawn out. Usually this test is done at the same time as a bone marrow biopsy.

Bone Marrow Biopsy

A test to find abnormal marrow cells. The area around the hip bone is numbed and then a special needle is inserted and a piece of bone containing marrow is withdrawn. Usually this test is done at the same time as a bone marrow aspiration.

Bone Marrow Transplantation

See Allogeneic Stem Cell Transplantation; Autologous Stem Cell Transplantation

Cancer-related fatigue (cancer treatment-related fatigue)

Cancer-related fatigue (CRF) is characterized by excessive and persistent exhaustion that interferes with daily activity and function. It often begins before cancer is diagnosed, worsens during the course of treatment, and may persist for months and even years after treatment ends. Compared with fatigue that healthy people experience, CRF is more severe, particularly relative to the person's activity or level of exertion. CRF is also less likely to be relieved by sleep or rest. CRF is generally either attributable to effects of the cancer or to the cancer treatment (for example, chemotherapy, radiation, immunotherapy), although the specific cause of a person's CRF may not be identifiable.


A catheter can be used to give IV fluids, blood products and other medications, such as antibiotics, and to draw blood for testing.


An antigen on CLL cells and other cells. The expression of CD38 may be a marker to assist in predicting CLL progression.

Cellular Immunity

That portion of the immune system that protects the individual from infection by the action of T lymphocytes, monocytes, macrophages and other specialized lymphocytes called NK cells. Deficiency in this portion of the immune system can permit infection by microbes such as the bacillus of tuberculosis, cytomegalovirus, and many other organisms that might be fended off more easily in a healthy individual. T lymphocytes also cooperate with B lymphocytes to increase the effectiveness of antibody formation.

Central Line (Indwelling Catheter)

A special tube put into a large vein in the patient’s upper chest. It is used to give medications, fluids or blood products or to take blood samples. See Port.

Central Nervous System (CNS) Prophylaxis

In certain types of leukemia, particularly acute lymphoblastic leukemia and acute monocytic leukemia with high blood cell counts, there is a propensity of the leukemic cells to enter the covering of the spinal cord and brain (the meninges). This process is often not apparent until months or years after remission when the leukemia returns, first in the coverings of the CNS, then in the marrow and blood. To prevent this type of relapse (meningeal leukemia), virtually all children and adults with acute lymphblastic leukemia who enter remission are treated by placing appropriate chemotherapy in the fluid that bathes the spinal cord and brain to prevent the leukemia from returning in these sites. In some cases, x-ray therapy is administered to the head as well. These approaches are very effective in eliminating leukemia cells in the coverings of the brain and spinal cord.


These are small molecules which may stimulate inflammation and which may play a role in stem cell mobilization.


A treatment that uses medicine (chemical agents) to kill cancer cells.


A solid tumor composed of immature granulocytes, including blast cells. Chloromas tend to occur in the brain or spinal cord, bones, skin, or soft tissue of the head and neck, although they can develop anywhere in the body. They are usually treated with radiation or chemotherapy. Chloromas are an uncommon complication of AML. Other terms for chloroma are "granulocytic sarcoma" and "extramedullary myeloblastoma."


Threadlike structures within cells that carry genes in a linear order. Human cells have 23 pairs of chromosomes: chromosome pairs 1 to 22 and one pair of sex chromosomes (XX for females and XY for males). See Translocation.

Clinical trials

Careful studies done by doctors to test new drugs or treatments, or new uses for approved drugs or treatments. The goal of clinical trials for blood cancers is to improve treatment and quality of life and to find cures.


The designation for a population of cells derived from a single transformed parent cell. Virtually all cancers are derived from a single cell with an injury (mutation) to its DNA and thus are monoclonal. Leukemia, lymphoma, myeloma and myelodysplastic syndromes are examples of clonal cancers; that is, cancers derived from a single abnormal cell.

Clonal Anemia (Clonal Pancytopenia)

Terms that may be used instead of "acquired" or "refractory" anemia. The terms "acquired" and "refractory" do not indicate the malignant (cancerous) nature of these disorders. A clonal disorder is a cancer.

Cluster Designation (CD)

A term used with a number to identify a specific molecule on the surface of an immune cell. It is commonly used in its abbreviated form, for example, “CD20” (the target of the monoclonal antibody therapy rituximab [Rituxan®] and “CD52” (the target of the monoclonal antibody therapy alemtuzumab [Campath®])

Colony Stimulating Factor

See Growth Factor.

Combination chemotherapy or drug therapy

Using two or more drugs together to fight a disease.

Combined Modality Therapy

Two or more types of treatment used alternately or at the same time to treat a patient's disease. For example, treating a patient with chemotherapy and involved field radiation therapy is a combined modality therapy.

Complete blood count (CBC)

A series of tests used to measure levels of red cells, white cells, and platelets in the blood, and the appearance of cells on a blood film. The CBC is used diagnose and manage many diseases.

Complete Cytogenetic Response

A response to treatment in which there are no cancer cells in the marrow that can be detected by FISH.

Complete Hematologic Response

A response to treatment in which the number of cancer cells is decreased, immature cancer cells are mostly eliminated from the blood and the hemoglobin concentration, white cell count and platelet count are at or near normal values.

Complete Molecular Response

A response to treatment in which polymerase chain reaction (PCR) testing reveals no evidence of cells containing cancer genes (oncogenes).

Complete Remission

When there is no sign of the disease based on the results of standard tests specific to that disease.

Computed Tomography (CT)

A special procedure that uses x-rays to take pictures inside a person’s body.

Conditioning Treatment

Intensive therapy of a patient with cytotoxic drugs or drugs and total body radiation just before receiving a stem cell transplant. The therapy serves three purposes. First, it severely depresses the lymphocytes that are the key cells in the recipient's immune system. This action helps prevent the rejection of the graft. Second, it markedly decreases the marrow cells, which may be important to open up the special niches where the transplanted stem cells must lodge to engraft. Third, if the patient is being transplanted for a malignancy, this intensive therapy greatly decreases the numbers of any remaining tumor cells.

Consolidation Therapy

A term usually applied to the treatment of acute leukemia for drug treatment given to patients in remission after induction therapy. The aim of consolidation therapy is to kill as many of the remaining cancer cells as possible.

Contrast Dye

A substance used during certain types of imaging tests to help distinguish between different body tissues and to clarify test findings. It is usually injected into a vein or given by mouth before the test. Contrast dyes are also called "contrast agents."

Cord Blood Stem Cells

Stem cells that are present in blood drained from the placenta and umbilical cord (the link that attaches a mom to a new baby). These stem cells have the capability to repopulate the marrow of a compatible recipient and produce blood cells. Frozen cord blood is a source of donor stem cells for transplantation to HLA-matched recipients. Most cord-blood transplants are given by either matched or nearly matched unrelated donors.


A technique used to keep frozen cells intact and functional for many years. Blood or marrow cells, including stem cells, can be stored for very long periods and remain functional if they are suspended in a fluid that contains a chemical that prevents cellular injury during freezing or thawing. This chemical is referred to as a "cryoprotective" agent. Dimethyl sulfoxide (DMSO) is one of the most commonly used agents. The freezing temperature is much lower (colder) than that of a household freezer.


A sample of bodily fluid, such as sputum, blood, and urine and swabs of the inside of the nose, throat, and rectum, which are used to determine the principal site and the type of bacterium, fungus, or other microorganism involved so that the most specific antibiotic can be selected as treatment.

Cycle of Treatment

The designation for an intensive, clustered period of chemotherapy and/or radiation therapy. The therapy may be given for several days or weeks, and this time period represents one cycle of treatment. The treatment plan may call for two, three or more cycles of treatment.

Cytogenetic Analysis

A type of test that looks at the number and size of the chromosomes in cells. It is often used in cancer treatment and to see changes in the cells before and after treatment.

Cytogenetic response (cytogenetic remission)

A treatment response in which there is no leukemia, lymphoma or myeloma cells detected in the blood and/or marrow by the FISH test.


A health care expert who uses special types of tests to look at cells and chromosomes


Cell- (cyto-) derived chemicals that are secreted by various types of cells and act on other cells to stimulate or inhibit their function. Chemicals derived from lymphocytes are called "lymphokines." Chemicals derived from lymphocytes that act on other white cells are called "interleukins"; that is, they interact between two types of leukocytes. Some cytokines can be made commercially and used in treatment. Granulocyte-colony stimulating factor (G-CSF) and granulocyte macrophage-colony stimulating factor (GM-CSF) are examples of cytokines. These stimulate the production of neutrophils and shorten the period of low neutrophil counts in the blood after chemotherapy. Cytokines that stimulate cell growth are sometimes referred to as "growth factors."


A reduction in the number of cells circulating in the blood.

Cytotoxic Drugs

Anticancer drugs that act by killing or preventing the division of cells. (See Chemotherapy.)


A mutation in which a part of a chromosome or a sequence of DNA is lost during DNA replication.


To detect a disease from a person’s signs, symptoms and test results. The doctor diagnoses a patient.


To detect a disease from a person’s signs, symptoms and lab test results. The doctor diagnoses a patient.


When stem cells develop and mature and take on a new function. Stem cells will either mature into red blood cells, platelets or white blood cells. See Hematopoiesis.

Disease subtype

A term used to describe a form of leukemia, lymphoma, myeloma, myelodysplastic syndromes and other diseases. The disease subtype is often important in determining how to treat the patient.


Deoxyribonucleic acid. The genetic matter found in all cells. DNA is passed to new cells during the process of cell division. A change or mutation in the DNA can lead to cell death, changes in the cell function, and in some cases, cancer.

DNA Repair Enzyme Inhibitors

Chemotherapy drugs that prevent certain cell proteins from working and make the DNA more susceptible to injury.

DNA Synthesis Inhibitors

Chemotherapy drugs that react with DNA to alter it chemically and keep it from permitting cell growth.

DNA-Gene Chip

See Microarray.

Donor lymphocyte infusion (DLI)

A therapy often used for patients after an allogeneic bone marrow transplant. In this procedure, patients are given lymphocytes (white blood cells) that come from the original transplant donor to help attack remaining cancer cells.

Drug resistance

When a drug does not work or stops working.

Drug therapy

Treatment with chemical agents to treat a disease.


The process of transplanted stem cells homing to the recipient's marrow and producing blood cells of all types. This occurrence is first evident when new white cells, red cells, and platelets begin to appear in the recipient's blood following transplantation.


A white blood cell that helps to fight some parasitic infections and participates in allergic responses.

Epigenetic Change

Any change that alters gene activity without changing the DNA sequence. Many types of epigenetic changes have been identified. While epigenetic changes are natural and essential to many of the body's functions, certain epigenetic changes can cause major adverse health effects, including cancer. Drugs that target specific epigenetic changes - for example, the histone deacetylase (HDAC) inhibitor vorinostat (Zolinza® )- are approved to treat some blood cancers and are being studied in clinical trials for treatment of other blood cancers

Erythrocyte Sedimentation Rate (ESR)

See Sedimentation Rate.


See Red Blood Cells.


See Hematocrit.

Erythropoietin (EPO)

A hormone needed for normal production of red blood cells. It is made mainly by the kidneys and is released into the blood due to decreased blood oxygen levels. Synthetic EPO is available as erythropoiesisstimulating agents (ESAs). Epoetin alfa (Procrit® or Epogen®) and darbepoetin alfa (Aranesp®) are ESAs that are used to treat anemia.

Extracorporeal Photopheresis

A procedure being studied to treat steroid-refractory graft versus host disease (GVHD). The procedure involves a series of treatments. Blood is removed through a vein, then white cells are isolated and treated with methoxsalen (UVADEX®), a drug that sensitizes the cells to ultraviolet light. UVA rays are used to irradiate the cells, which are then reinfused into the patient.


Located or taking place outside the bone marrow.

Extranodal Lymphoma

Lymphoma that has spread outside the lymph nodes to the organs-the thyroid, lung, liver, bone, stomach or central nervous system. Physicians adjust their therapeutic approach if organs outside of lymph nodes are involved. If the brain, liver or bones are involved, for example, the treatment approach is likely to target these areas. If lymphoma is found in any of the organs but not in lymph nodes or multiple lymphatic sites, the disease is called a "solitary extranodal lymphoma."

Farnesyl Transferase Inhibitor

A drug that has the potential to kill cancer cells by inhibiting or reversing the effect of farnesyl transferase, an enzyme needed to activate oncogenes (cancer-causing genes). FTIs, including tipifarnib (Zarnestra®) and lonafarnib (Sarasar®), are being studied to treat myelodysplastic syndromes and other blood cancers.


The short name for the US Food and Drug Administration. Part of the FDA’s job is to assure the safety and security of drugs, medical devices and the US food supply.


An imaging technique used to locate lymphoma masses. PET is combined with CT to establish the precise location of lymphoma masses and, compared to other imaging procedures, PET can detect much smaller lymphoma masses.

Flow Cytometry

A test that finds specific cell types within a cell sample, During this test, cells flow through the instrument called a “flow cytometer.” When the cells pass through its laser beam, those with the antibody-specific features light up and can be counted. This test may be used to examine blood cells, marrow cells, or cells from a biopsy.

Fluorescence In Situ Hybridization (FISH)

A technique to study chromosomes in tissue. It uses probes with fluorescent molecules that emit light of different wavelengths and colors. The probes match to the chromosomes within the cells, and the chromosomes fluoresce in color. FISH can be helpful in assessing risk and treatment needs, and for monitoring treatment effectiveness, by providing a sensitive test to see abnormal cells, such as cells with deletions of 17p.

Fluorodeoxyglucose (FDG)

A substance that is similar to glucose (a type of sugar) with a radioactive tracer (F-18) attached to it. FDG is injected into a patient's blood, and its activity in the body is traced using a PET scan. Because tumor cells consume significantly larger amounts of glucose than normal cells in surrounding tissue do, FDG-PET is an effective tool for detecting lymphoma and other cancers.

FMS-like tyrosine kinase 3 gene (FLT3)

An abbreviation for the FMS-like tyrosine kinase 3 gene. FLT3 is expressed on blood forming stem cells and plays a role in cell development. FLT3 mutations can be detected in about one-third of AML patients. These mutations have been identified as part of the AML disease process and may become the basis for new targeted therapies.

Fractionation of the Dose

In order to minimize the significant side effects of total body irradiation conditioning therapy, the dose of radiation required is given in several daily smaller doses rather than one larger dose. This approach has decreased the adverse effects of this treatment.

Gamma Globulins

A portion or fraction of the proteins that are in plasma. The three major groups of globulins are called "alpha," "beta," or "gamma" globulins. Gamma globulins are sometimes referred to as "immune globulins" or "immunoglobulins" because they are made by the immune cells, specifically B lymphocytes and plasma cells. Gamma globulins are key elements of the immune system because they protect the body from infection. Patients with immune deficiencies whose B lymphocytes cannot make gamma globulin (such as patients with chronic lymphocytic leukemia and some patients with lymphoma) may be given injections of gamma globulin periodically in an effort to decrease the risk of infection.

G-Banding Karyotyping

A testing method that makes a certain characteristic of chromosomes easier to see. A “karyotype” is the systematic arrangement, using images, of the 46 human chromosomes of a cell. Karyotypes are examined for deviations from the expected arrangement, number, size, shape or other characteristics of the chromosomes. Each chromosome pair has a characteristic banding pattern. To make the banding pattern easier to see, a dye called “Giemsa” may be used as a stain. This process is also referred to as “G-banding.” G-banding karyotyping and other cytogenetic tests provide doctors with information that contributes to determining the best treatment approach for an individual patient. The test takes longer than the FISH test, but has the advantage of being able to detect any changes that are visible because it does not rely on specific probes. Usually, both tests are done on samples from the marrow, especially at the time of diagnosis.

G-CSF (Granulocyte-Colony Stimulating Factor)

See Growth Factor.

Gene Expression Profiling

A research method that uses microarray analysis to identify a combination of genes that are turned off or on in response to a specific condition. A set of genes in a blood or tissue sample can be use to monitor the levels of thousands of genes at once. Gene expression profiling is used to help identify cancer subtypes and risk factors as an aid in predicting treatment response and which patients may be at increased risk for relapsed disease. Microarray analysis and related techniques may also lead to the discovery of new treatment targets. (See Microarray Analysis).


Parts of cells that give instructions for making proteins. Proteins help the cell do its job.

Germ-Cell Mutation

A mutated cell in the egg or the sperm is passed from parent(s) to offspring. See Mutation.

Gleevec (imatinib mesylate)

A type of drug called a tyrosine kinase inhibitor. It is FDA approved for newly diagnosed adult patients with Ph positive CML in chronic phase. It is also approved for adults with Ph positive CML in blast crisis phase, accelerated phase, or in chronic phase after failure of interferon alpha therapy. Gleevec is approved for children with Ph positive CML in chronic phase who are newly diagnosed.

GM-CSF (Granulocyte Macrophage-Colony Stimulating Factor)

See Growth Factor.

Graft versus cancer effect

With an allogeneic stem cell transplant, the donated stem cells make immune cells that are not totally "matched" with the patient's cells. For this reason, the donor immune cells may recognize the patient's cancer cells as foreign and kills them.

Graft-Versus-Host Disease (GVHD)

A disease that happens when the donor cells (“the graft”) attack the cells of the patient (“the host”). Most often this disease attacks a patient’s skin, liver, and the stomach and gastrointestinal tract.

Graft-Versus-Tumor Effect (Graft-Versus-Leukemia Effect)

The potential immune reaction of transplanted (donor) T lymphocytes causing them to recognize and attack the cancer cells of the patient.


A type of white blood cell with many particles (granules) in the cell body. Neutrophils, eosinophils and basophils are types of granulocytes.

Granulocytic Sarcoma

A localized tumor of leukemic cancer cells. These tumors are found outside the marrow, may occur beneath the skin or other places, and may be the first sign of leukemia


An increase above normal of the concentration of blood leukocytes (white cells)—specifically, granulocytes (neutrophils, eosinophils and basophils). This excludes lymphocytes and monocytes.

Growth Factor

A substance used to increase the numbers of neutrophils after chemotherapy. Granulocyte-colony stimulating factor (G-CSF) and granulocyte-macrophage colony stimulating factor (GM-CSF) are growth factors that can be made in the lab.


A potential stem cell donor that has a 50 percent HLA antigen-match with a patient. Parents are haploidentical with children. Siblings have a 50 percent chance of being haploidentical. See HLA; Allogeneic Stem Cell Transplantation.


The tissue type contributed by either the mother or father to his or her offspring. It is implied that it represents the genes on one parental chromosome. When a transplant procedure is between a donor and recipient that are haplotype identical, it means that the tissue type or HLA type of each is identical in respect to mother or father but not identical to the other. In some situations, if the discrepancy is not too great, the transplant may still be possible if the underlying disease makes the risk of partial compatibility warranted. Conditioning of the recipient and lymphocyte depletion of the donor stem cell suspension are steps taken to mitigate the risk of immune cell activation by the tissue type differences.

Hasford Scoring System

A scoring system that estimates survival of patients with chronic myeloid leukemia. The system designates patients as low-risk, intermediaterisk or high-risk.


See Apheresis.


The portion of the blood occupied by red blood cells. Normal amounts are 40 to 54 percent in males and 35 to 47 percent in females. Anemia occurs when the hematocrit level is below normal; erythrocytosis occurs when the hematocrit level is above normal.

Hematologic response (hematologic remission)

A treatment response where the leukemia, lymphoma or myeloma cell numbers are decreased in the blood; and, red cell count, white cell count, and platelet count are either at or near normal values.


A doctor who specializes in blood cell diseases.


A doctor or scientist who studies the blood cells and blood tissues to identify disease.


The formation of all types of blood cells that starts in the marrow. For the blood cell development process.


The iron-containing substance in red blood cells that carries oxygen around the body. Hemoglobin concentration decreases when there is a reduction in the number of red blood cells. This condition is called “anemia.”

Histone Deacetylase Inhibitor (HDAC Inhibitor)

A substance that causes a chemical change that stops cancer cells from dividing. HDAC inhibitors appear to have a greater effect on cancer cells than on normal cells. As a result they may cause less toxicity than other chemotherapeutic agents.

HLA (human leukocyte-associated antigen)

Human leukocyte-associated antigen. Proteins on the outer part of the cells that help fight illness. HLAs are passed from parents to their children and one in four siblings has the same type of HLA.


The recipient of the transplant who acts as "host" to the transplanted stem cells.


An abnormally high concentration of calcium in the blood. Hypercalcemia can contribute to weakness, loss of appetite, nausea, confusion, constipation, lethargy and other symptoms.


A very high white blood cell count, often found in people when they are diagnosed with leukemia.

Immune response

The reaction of the body to foreign material. Examples of foreign material are an infection-causing microorganism, a vaccine, or the cells of another person used for an allogeneic stem cell transplant.

Immune system

A system within the body that works to fight disease and infection.


The ability to resist infection.

Immunoconjugate (Therapeutic Immunoconjugate)

A monoclonal antibody fused to potent toxins or cytotoxic agents.

Immunoglobulin Heavy Chain Variable Region (IgHv) Gene Status

A marker that can distinguish between CLL subtypes (unmutated IgHv and mutated IgHv). People with CLL with unmutated IgHv gene status may have a more progressive form of the disease.


Proteins that fight infection.


A process used to find specific types of cells within a blood sample. It looks at antigens or markers on the surface of the cell to identify antibodies.


A state in which the immune system does not function properly and its protective functions are inadequate. The patient is more susceptible to infections, including those from microbes that are usually not highly infectious.


A treatment that uses the body’s immune system to treat diseases. Such therapies include - Monoclonal antibody therapy: a type of drug using antibodies designed to attack specific parts of the cancer cells - Radioimmunotherapy: a type of drug that uses radioactive substances and antibodies to attack cancer cells - Vaccine therapy: drugs used to stimulate the immune system to fight cancer cells.

Indolent myeloma

Slow-growing myeloma. Sometimes called "smoldering myeloma."

Induction therapy

The initial treatment with chemotherapy (or radiation therapy). The aim of induction therapy is to kill a maximum number of blood cancer cells so as to induce a remission (absence of signs or effects of the disease).

Indwelling Catheter

See Central Line.

Intensification Therapy

Another name for consolidation therapy.

Interstitial Pneumonitis

A severe inflammation in the lungs that can occur as a toxic effect of total body irradiation in the conditioning regimen. The small airways and intervening spaces between air sacs get congested, swollen, and exchange of oxygen can be compromised. Typically, no infection is present although a similar reaction can occur as a result of infection.


Designation for the space between the covering or lining of the central nervous system (CNS) and the brain or spinal cord. That lining is called the "meninges." In some situations drugs have to be administered directly into the spinal canal when cancer cells are in the meninges. This procedure is called "intrathecal therapy."


The order, number and appearance of chromosomes within a cell. There are 46 human chromosomes with the sex chromosomes shown as a separate pair (either XX or XY). The 22 pairs with each cell are called “autosomes.” See FISH (Fluorescence In Situ Hybridization).

Lactate Dehydrogenase (LDH)

An enzyme present in all normal and abnormal cells. It is released from cells into the blood and is present in normal amounts in the liquid portion of blood (the plasma). When blood is collected and allowed to clot, the fluid portion is called the "serum." Many chemicals are measured in the serum, including LDH. Normal serum contains low levels of LDH. The level may be elevated in many diseases, such as hepatitis and various cancers. Changes in LDH are nonspecific, but when LDH is elevated in the presence of certain cancers, the change may reflect the extent of the tumor and the rapidity of tumor growth. LDH monitoring is used in some cases along with other measures to plan the intensity of therapy.


A cancer of the marrow and blood. There are four main subtypes of leukemia: acute lymphoblastic leukemia, acute myeloid leukemia, chronic lymphocytic leukemia and chronic myeloid leukemia.

Leukocyte Alkaline Phosphate (LAP)

A test that measures the amount of a certain enzyme (alkaline phosphatase) in white blood cells. People with certain types of blood cancer often have low LAP levels.


See White Blood Cells


An increase above the upper limit of normal in the concentration of blood leukocytes (white blood cells).


A decrease below normal in the number of leukocytes (white blood cells) circulating in the blood.

Light chains

Parts of the monoclonal (M) protein in myeloma. When excreted in large amounts, the light chain protein can cause injury to the kidneys and kidney failure. Also known as the "Bence Jones Protein."

Long-term effects

Medical problems that persist for months or years after treatment ends, for example, infertility, growth problems in children, or cancer treatment-related fatigue.

Lumbar Puncture

A procedure to remove spinal fluid from the space surrounding the spinal cord or to administer anticancer drugs to either prevent or treat leukemia or lymphoma of the coverings of the central nervous system. The doctor will first use a local anesthetic, then insert a needle between two vertebrae in the lower part of the back. Fluid samples are collected in sterile tubes and examined for evidence of leukemia or lymphoma. This procedure is also called a "spinal tap."

Lymph nodes

Small structures, the size of beans that contain large numbers of lymphocytes and are connected with each other by small channels called “lymphatics.” These nodes are distributed throughout the body. In patients with lymphoma and some types of lymphocytic leukemia, the malignant lymphocytes grow and expand the lymph nodes so that they may become enlarged.


Enlargement of lymph nodes.

Lymphatic System

The system comprising the lymph nodes, the thymus gland (in the first several decades of life), the lymphatic channels, the lymphatic tissue of the marrow, the gastrointestinal tract, the skin and the spleen, along with the T, B and Natural Killer (NK) lymphocytes contained in those sites.

Lymphatic vessels

These channels connect the lymph nodes. They contain lymph, a fluid that carries lymphocytes as they circulate from one lymph node area to another. The lymphatic channels are connected to the blood vascular system permitting lymphocytes to enter the blood.


The leukemic cell that replaces the normal marrow cell. Uncontrolled and exaggerated growth and accumulation of these leukemic cells means that they fail to function as normal blood cells.


A term used to describe a type of blood cell disease caused by young or immature lymphocytes or "lymphoblasts." An example is acute lymphoblastic leukemia, which is characterized by the presence of malignant (cancerous) lymphoblasts (immature lymphocytes).


A type of white blood cell that is important to the body’s immune system. There are three major types of lymphocytes: B lymphocytes, which produce antibodies to help combat infectious agents such as bacteria, viruses and fungi; T lymphocytes, which have several functions, including assisting B lymphocytes in making antibodies; and natural killer (NK) cells, which can attack virus-infected cells or tumor cells.


See Cytokines.

M protein

Monoclonal immunoglobulin, a protein made by myeloma cells. This protein, also called "M protein," enters the blood. The amount of M protein in the blood can be measured. It is used to estimate the extent of the myeloma.


A monocyte in action (this is called a “scavenger cell”). When monocytes leave the blood and enter the tissue, they are known as “macrophages.” Macrophages fight infection, eat dead cells and help lymphocytes with their immunity functions. See Monocyte.

Magnetic Resonance Imaging (MRI)

A test that uses magnetic fields and radio waves to create images of the body’s organs and tissue.

Maintenance Therapy

Chemotherapy given to ALL patients after several weeks of induction and consolidation therapy to help destroy the remaining ALL cells. Maintenance therapy is given for about two years.


See Bone Marrow.

Matched donor

A person whose major tissue types are identical to those of a patient who is seeking a stem cell transplant. The patient can be given the donor's healthy matched stem cells, which can restore blood and immune cells after high-intensity cancer treatment.


See Hematopoiesis.


See Intrathecal.


A two-dimensional grid of molecules (often but not always DNA genes or gene fragment spots), usually arranged on a glass slide or silicone wafer. A typical microarray (also called "DNA-gene chip") contains 10,000 to 200,000 microscopic DNA spots. Scientists use a microarray to study gene expression and to learn which genes are expressed and not expressed under given circumstances. See Gene Expression Profiling.

Microliter of blood

A measurement used for some blood test results. One ?L is about one-millionth of a quart of blood.

Minimal Residual Disease (MRD)

The small amounts of cancer cells that may remain after treatment. These cells are only identified by sensitive molecular techniques.

Molecular response

A treatment response is called a complete molecular remission if no leukemia cells in the blood and/or marrow can be detected by PCR.

Molecular Targeted Therapy

See Tyrosine Kinase Inhibitor (TKI).


See Clonal.

Monoclonal Antibodies

Antibodies made by cells of a single clone. They are used in cancer treatment to target cancer cells. They can be made in a lab.

Monoclonal Antibody Therapy

Immune proteins made in the laboratory. This type of therapy targets and kills specific cancer cells. It does not cause many of the side effects of chemotherapy.


A type of red blood cell that represents about 5 to 10 percent of the cells in normal human blood.

Mucous Membranes

The inner lining of cavities such as the mouth, nose, and sinuses. These linings require new cells to be made to replace those that drop off. This replacement is a normal process and keeps the lining intact and moist. Radiation therapy or chemotherapy drugs that block cells from dividing prevent the replacement of lost cells. The linings become dry, defective, and may ulcerate in patients who receive such treatment. This change can be painful, such as when ulcers develop in the mouth. These painful, ulcerating lesions are referred to as oral "mucositis." Anal ulcers can also develop. The loss of what is referred to as the barrier function of mucous membranes permits microbes to enter the tissue or blood and often leads to infection.

Multidrug Resistance (MDR)

A cell characteristic that makes cells resistant to certain types of drugs.


A change in the DNA that makes up a gene.


See Blast Cells.


A marrow cell that is a precursor of the mature granulocytes of the blood. Myelocytes are not present in the blood of healthy individuals.


See Refractory Anemia; Refractory Anemia With Ring Sideroblasts.

Myelodysplastic Syndromes

Cancer of the blood and marrow. It happens when the cells in the bone marrow are damaged. There are many different myelodysplastic syndromes.


A term used to describe a form of blood cancer that begins in a marrow stem cell or early marrow progenitor cell.

Myeloma Cells

Malignant plasma cells that are the hallmark of myeloma. Their appearance may be similar to normal plasma cells, but they are present in increased numbers.

Myeloproliferative Neoplasms (MPNs)

A group of diseases that occur when certain types of blood cells are overproduced. Examples of MPNs are essential thrombocythemia, polycythemia vera and myelofibrosis. Some people with MPNs have abnormal-looking cells in their bone marrow that are similar to MDS cells.


An abnormal decrease in the number of neutrophils, a type of white blood cell, in the blood.


A type of white blood cell and the main type that works to fight infection. People with some blood cancers, or those who have received treatment (such as chemotherapy) for cancer, often have low neutrophil counts. People with low neutrophil counts are very susceptible to infections.

Nonmyeloablative Stem Cell Transplantation

See Reduced-Intensity Stem Cell Transplantation.

Nonsecretory Disease

In a small proportion of patients with myeloma, no abnormal protein can be detected.


A part of the cell containing the chromosomes and genes.

Oligoblastic Myelogenous Leukemia

Also known as “refractory anemia excess blasts” (RAEB), this type of MDS shows signs of leukemic blast cells when the blood or marrow is examined. There may only be a small number of these blast cells in the marrow, but their presence indicates that leukemic cells are developing.

Oligosecretory Disease

In a small proportion of patients with myeloma, the level of abnormal protein that is detected is low.


A changed (mutated) gene that contributes to the development of cancer. See Mutation.


A cancer doctor.

Opportunistic Infections

Unusual infections to which patients treated for cancer may be susceptible because of the suppression of their immune system. "Opportunistic" is the term used to describe infections with bacteria, viruses, fungi or protozoa to which individuals with a normal immune system are not susceptible. The infecting organisms take advantage of the opportunity provided by immunodeficiency, especially when coupled with very low white cell counts resulting from therapy or the disease itself.


A health condition when there is a decrease in the numbers of the three major blood cell types: red blood cells, white blood cells and platelets.

Partial Remission

When the disease is improved after treatment, but is still present.


A doctor who finds disease by examining body tissue and fluids.

Percutaneously Inserted Central Venous Catheter (PICC or PIC Line)

A long, thin, flexible tube placed into the body under the skin. It can be used for weeks or months to help give a patient medicine, fluid or nutrition. It can also be used to get blood samples. Intravenous (IV) infusions can be administered via a PICC line.

Peripheral Blood Smear

A sample of blood placed on a slide and stained (dyed) so that the cells can be examined under a microscope.


Pinhead-sized sites of bleeding in the skin that occurs when someone has a low platelet count. They are often seen on the legs, feet, trunk and arms. Petechiae turn from red to brown, and eventually disappear. They stop developing when the platelet count increases.


Cells that protect the body from infection by eating and killing microorganisms such as bacteria and fungi. Neutrophils and monocytes are the two main types of these cells. Once an infection occurs, phagocytes migrate from the bloodstream and enter the infected tissue. Chemotherapy and radiation can decrease the numbers of these cells, so patients are more likely to get an infection.

Philadelphia Chromosome (Ph Chromosome)

An abnormality of chromosome 22 found in the marrow and blood cells of patients with chronic myeloid leukemia and of some patients with acute lymphoblastic leukemia. The abnormality, a shortening of the long arm of this chromosome, was first observed and reported by doctors at the University of Pennsylvania in Philadelphia; thus the name “Philadelphia chromosome.” In most cases, the lost piece of chromosome 22 sticks (translocates) to chromosome 9. Indeed, some of chromosome 9 also sticks (translocates) to chromosome 22. This circumstance is referred to as a “balanced translocation,” because virtually equal lengths of partial chromosome arms exchange position. Because chromosome 22 is a very short chromosome and chromosome 9 is a very long one, the lengthening of chromosome 9 was less apparent than the shortening of 22 until more sensitive detection techniques became available. The abnormality of chromosome 22 is now usually abbreviated as “Ph chromosome.

PICC or PIC Line

See Percutaneously Inserted Central Venous Catheter


The liquid part of the blood.

Platelet Transfusion

This procedure transfers blood platelets from one patient to another. About six single-unit blood donors are often needed to provide enough platelets to raise the patient's platelet level. For more information, see the free LLS publication Blood Transfusion. See HLA; Apheresis


Also known as “thrombocytes,” platelets are small colorless blood cells. They travel to and collect at the site of a wound. Once they get there, the platelets' sticky surface helps them to form clots and stop bleeding. Platelets make up about one tenth of the volume of red blood cells.

Polymerase Chain Reaction (PCR)

A technique to expand trace amounts of DNA or RNA so that the specific type of the DNA or RNA can be studied.


A small device placed under the skin and attached to a central line or a peripherally inserted central catheter (PICC or PIC line). It permits access to the line. Medicines and nutrition can be administered and blood samples can be withdrawn via a port.

Positron Emission Tomography (PET) Scan

Abbreviated as "PET scan," this test may be used as a follow-up to other tests to determine if a tumor is malignant (cancerous) or benign. A PET scan may also be used to measure response to treatment for certain types of cancer. For a PET scan, glucose (a type of sugar) is labeled with a positron particle emitting a radioisotope, such as fluorine-18. Since cancer cells take up more glucose than normal cells, the radioisotope becomes concentrated in areas with cancer cells. Both a PET scan and a computed tomography (CT) scan may be done to establish the precise location of masses of cancer cells; this is called a PET-CT.

Postremission Therapy

The treatment given to ALL patients after induction therapy. Postremission therapy may have two parts: consolidation (or intensification) and maintenance.


A cell that is formed during the transition from an immature cell to a mature cell during the development cycle for certain types of red blood cells.


See Refractory Anemia.

Radiation Oncologist

A cancer doctor that uses radiation to treat cancer.

Radiation therapy

Treatment with x-rays or other high-energy rays.

Radioactive Isotope

A form of a molecule that emits radiation. Certain types of radiation can damage cancer cells. Physicians use radioactive isotopes to treat cancer in several ways, including attaching the isotope to antibodies. The antibodies can attach to the cancer cell, and the radiation can destroy it.


A treatment that uses antibodies to carry a radioactive substance to lymphoma cells to kill them. Radioimmunotherapy such as Zevalin® carries a radioactive substance to the lymphoma cells that then irradiates lymphoma cells locally and selectively. This approach minimizes the effects of radiation on normal tissues.


See Oligoblastic Myelogenous Leukemia.


See Refractory Anemia With Excess Blasts in Transformation.


See Refractory Anemia With Ring Sideroblasts.


See Refractory Cytopenia With Multilineage Dysplasia.


When disease comes back after it has been successfully treated.

Red Blood Cells

Blood cells (erythrocytes) contain hemoglobin, which carries oxygen to the tissues of the body. Red blood cells make up about 40 to 45 percent of blood volume in healthy people

Reduced-Intensity Stem Cell Transplantation

A type of allogeneic transplantation. Patients receive lower doses of chemotherapy drugs and/or radiation to prepare for a reduced-intensity transplant. This protocol may be safer than an allogeneic stem cell transplant–especially for older patients. See the free LLS publication, Blood and Marrow Stem Cell Transplantation.

Refractory ALL

ALL that has not responded to initial treatment. Refractory disease may be a disease that is getting worse or staying the same even after treatment (stable disease).

Refractory Anemia (RA)

Also known as “myelodysplasia,” this clonal myeloid disorder mostly affects red blood cell production in the marrow. It can also be associated with mild to moderate decreases in the numbers of white blood cells and platelets. In some classification systems, it is an MDS subtype.

Refractory Anemia with Excess Blasts (RAEB)

See Oligoblastic Myelogenous Leukemia.

Refractory Anemia With Excess Blasts in Transformation (RAEB-T)

In the French-American-British (FAB) classification, an MDS subtype in which the bone marrow blast count ranges from 20 to 30 percent

Refractory Anemia with Ringed Sideroblasts (RARS)

This is a form of anemia where the bone marrow produces ringed sideroblasts rather than healthy red blood cells (erythrocytes). In the case of abnormal sideroblasts, large amounts of iron are trapped in the developing red cells in abnormal sites. Refractory anemia and RARS are often associated with mild to moderate decreases in the numbers of white blood cells and platelets. This disorder is also called “myelodysplasia” or “acquired sideroblastic anemia.” In some classifications, RARS is an MDS subclass. Also called “myelodysplasia” or “acquired sideroblastic anemia.”

Refractory CLL

CLL that has not responded to initial treatment. Refractory disease may be disease that is getting worse or staying the same (stable disease).

Refractory CML

CML that has not responded to initial treatment. Refractory disease may be disease that is getting worse or staying the same (stable disease).

Refractory Cytopenia With Multilineage Dysplasia (RCMD)

One of the more common WHO MDS subtypes. There are too few of at least two types of blood cells (red blood cells, white blood cells, or platelets). In the bone marrow, those same types of cells look abnormal (dysplasia) under the microscope. Less than 5 percent of the cells in the bone marrow are blasts. In patients with more than 15 percent ringed sideroblasts, the subtype is called “RCMD-RS.”

Refractory Disease

A disease that does not go away or improve much after initial treatment.

Refractory lymphoma

Lymphoma that has not responded to initial treatment. Refractory disease may be disease that is getting worse or staying the same.

Refractory myeloma

Myeloma that has not responded to initial treatment. Refractory disease may be disease that is getting worse or staying the same.


A return of the disease after it has been in remission following therapy.

Relapsed CLL

CLL that responded to treatment but then returns.

Relapsed CML

CML that responded to treatment at first, but then returned.

Relapsed Disease

Disease that initially responded to therapy but has begun to progress.

Relapsed lymphoma

Lymphoma that responded to treatment but then returns.

Relapsed myeloma

Myeloma that responded to treatment but then returns.


When signs of a disease disappear. This usually follows treatment. The words “complete” and “partial” are sometimes used to further define the term “remission.” Complete remission means that all evidence of the disease is gone. Partial remission means that the disease is markedly improved by treatment, but residual evidence of the disease is present


When a drug does not work or stops working.

Resistance to Treatment

When cancer cells continue to grow even after strong drugs and/or treatments.

Richter transformation

In a small number of patients, there is a progression in their disease. In these patients, CLL takes on the characteristics of an aggressive lymphoma. This change is not a second cancer, but a transformation of the CLL cells.

Risk factor

Something that is scientifically linked to a person’s chance of getting a disease. Risk factors can be genetic (inherited), lifestyle related, or environmental.


Abbreviation for ribonucleic acid, a molecule in cells that carries out DNA's instructions for making proteins.

Salvage Therapy

Treatment for a person with cancer that has not responded to other primary treatment(s).

Sanctuary Sites

Areas in which it is difficult to get a sufficient concentration of chemotherapy to destroy leukemia cells. For example, in acute lymphoblastic leukemia, the coverings (meninges) of the brain and spinal cord and the testes are notable sanctuary sites.

Scavenger Cell

See Monocyte/Macrophage.

Sedimentation Rate

A blood test that measures how quickly red cells (erythrocytes) settle in a test tube in one hour. A sedimentation rate test is done to find out if inflammation is present in the body, to check on the progress of a disease or to see how well a treatment is working. This test is also called a "seed rate" or "erythrocyte sedimentation rate (ESR)."


The liquid portion of the blood. See Lactate Dehydrogenase (LDH).

Side effect

The signs or symptoms a patient may have from the effects of treatment on healthy cells.

Signs and symptoms

Changes in the body that show disease. A sign is a change that the doctor sees in an exam or a lab test result. A symptom is a change that a patient can see or feel.

Small lymphocytic lymphoma (SLL)

A disease with symptoms and treatment that are much like CLL. SLL starts in a lymphocyte in a lymph node. CLL starts in a lymphocyte in the marrow.

Smoldering Leukemia

See Oligoblastic Myelogenous Leukemia.

Sokal Scoring System

A scoring system used for patients with chronic myeloid leukemia that estimates their survival. Patients are rated low risk, intermediate, or high risk based on their spleen size, platelet count, age and blast count. It is also used to predict the response to tyrosine kinase inhibitors (TKIs). TKIs are a type of drug used to treat CML.

Solitary Extranodal Lymphoma

See Extranodal Lymphoma.

Somatic Cell Mutation

A change in the DNA that occurs in a specific tissue cell which may result in a tumor. Most cancers start after a somatic cell mutation.

Spinal Tap

See Lumbar Puncture.


This organ in the left upper portion of the abdomen just under the left side of the diaphragm, acts as a blood filter. Enlargement of the spleen is called “splenomegaly.” Surgical removal of the spleen is known as “splenectomy.”


Surgical removal of the spleen.


Enlargement of the spleen.

Sprycel (dasatinib)

A tyrosine kinase inhibitor that is FDA approved for the treatment of newly diagnosed adult patients who have Ph positive CML in chronic phase and adults in all phases of CML (chronic, accelerated, or blast phase) who have resistance or intolerance to prior therapy including Gleevec.

Stem Cell Transplantation

See Allogeneic Stem Cell Transplantation; Autologous Stem Cell Transplantation.

Stem Cells

Primitive marrow cells that mature into red blood cells, white blood cells, and blood platelets. Stem cells are mostly found in the marrow, but some leave and circulate in the bloodstream. Stem cells can be collected, preserved, and used for stem cell therapy. See Hematopoiesis.

Tasigna (nilotinib)

A type of drug called a tyrosine kinase inhibitor that is FDA approved for the treatment of newly diagnosed adult patients with Ph positive CML in chronic phase and adults in chronic phase and accelerated phase Ph positive CML who are resistant or intolerant to prior therapy that included Gleevec.


A synonym for “platelet.”


A disorder characterized by too many platelets in the blood.


A disorder characterized by too few platelets in the blood.

Tissue Typing

A test for the presence of HLA antigens.


A very important event in the long-term success of transplantation. After a time, usually a year or so, the prior host and donor T lymphocytes die off and new lymphocytes are formed from the donor?s engrafted stem cells. These "adapt" to the new host and stop attacking the recipient's cells. If tolerance is present, the immune system is no longer distracted and can serve the patient by working efficiently to protect against microbes. Risk of infection diminishes and approaches that of a healthy person. Immunosuppressive therapy can be stopped.


A naturally derived substance that is poisonous to cells. A toxin can be attached to antibodies that then attach to cancer cells. The toxin may kill the cancer cells.


An abnormality of chromosomes in the marrow or lymph node cells that occurs when a piece of one chromosome breaks off and attaches to the end of another chromosome. In a balanced translocation, genetic material is exchanged between two different chromosomes with no gain or loss of genetic information. When a translocation takes place, the gene at which the break occurs is altered. This is one form of somatic mutation that may transform the gene into an oncogene (cancer-causing gene). See Mutation.


See Allogeneic Stem Cell Transplantation; Autologous Stem Cell Transplantation.

Tumor Suppressor Gene

A gene that works to stop cell growth.

Tyrosine Kinase

A type of enzyme that plays a key role in cell function. It is normally present in cells, and a normal gene, ABL on chromosome 9, directs its production. In chronic myeloid leukemia, an alteration in the DNA results in a mutant fusion gene, BCR-ABL, which produces an abnormal or mutant tyrosine kinase. This abnormal enzyme leads to a cascade of effects in the cell that transforms it into a leukemic cell.

Tyrosine kinase inhibitor (TKI)

A type of drug, which includes widely used imatinib mesylate (Gleevec®). These drugs block the effects of the mutant BCR-ABL tyrosine kinase found in CML. This specific approach to cancer therapy is referred to as “molecular-targeted therapy” since the drug is designed to block the effect of a specific protein that is the essential cause of the leukemic transformation. Dasatinib (Sprycel®) and nilotinib (Tasigna®) are second-generation TKIs. They are being used either as initial treatment or after therapy when patients prove resistant to or cannot tolerate Gleevec. Bosutinib (Bosulif®) is approved for patients with resistance to Gleevec and other TKIs, and ponatinib (Iclusig) is approved for patients with the drug-resistant T315I mutation as well as patients without other TKI options.

Unclassified MDS (MDS-u)

A WHO MDS subtype classification that includes patients who do not have refractory anemia or other MDS subtypes, but have either neutropenia or thrombocytopenia with unusual features, such as marrow fibrosis. The number of blasts in the blood and bone marrow is not increased.

Vaccine therapy

A type of treatment under study for leukemia, lymphoma, or myeloma. This type of vaccine would not prevent the disease. The vaccine would increase the immune system's attack against cancer cells that remain after treatment with drugs.

Veno-occlusive disease (VOD)

A disease that may be a complication following high-dose chemotherapy and/or radiation, in which the blood vessels that carry blood through the liver, swell and become clogged.

Watch and wait (watchful waiting)

An approach in which a physician closely observes a patient's condition with periodic medical exams and lab tests, without giving drugs or other forms of treatment for the disease in question.

White Blood Cells

Also known as “leukocytes,” the five types of infectionfighting cells in the blood. These include neutrophils, eosinophils, basophils, monocytes and lymphocytes.


An abbreviation for the cell protein “zeta-associated protein 70.” A high level of ZAP-70 expression on the cells of patients with B-cell CLL is one of several factors that may predict more progressive disease. Outside of a research laboratory this test is generally not very reliable and should not be used.


Lymphoma is the name for a group of blood cancers that develop in the lymphatic system. The two main types are Hodgkin lymphoma and non-Hodgkin lymphoma (NHL).


A type of cancer that begins in the bone marrow. It is a cancer of plasma cells, which are a type of white blood cells (also called plasma B cells).


When a section of DNA breaks away and reattaches to the chromosome in a reversed order. This can be a small section of DNA that breaks away or a large section containing many different genes.


A gene involved in normal cell growth. Mutations (changes) in a proto-oncogene may cause it to become an oncogene, which can cause the growth of cancer cells.


An extra copy of a chromosome.


A mutation in which a part of a chromosome or a sequence of DNA is lost during DNA replication.


When a section of DNA breaks away and reattaches to the chromosome in a reversed order. This can be a small section of DNA that breaks away or a large section containing many different genes.


An abnormality of chromosomes in the marrow or lymph node cells that occurs when a piece of one chromosome breaks off and attaches to the end of another chromosome. In a balanced translocation, genetic material is exchanged between two different chromosomes with no gain or loss of genetic information. When a translocation takes place, the gene at which the break occurs is altered. This is one form of somatic mutation that may transform the gene into an oncogene (cancer-causing gene). See Mutation.