About Diseases

The definitions below are provided for your general information. Your medical team will have more detailed and specific information related to your diagnosis. Is there a term we haven't defined that you would like to see included? E-mail us and we'll look in to it! Thanks!

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A rapidly progressive cancer of the blood of sudden onset and characterized by the uncontrolled proliferation of immature blood cells, which take over the bone marrow and spill into the blood stream. The leukemia cells can't do any of the work of normal white blood cells. The number of leukemia cells increases rapidly. Acute leukemia usually worsens quickly.

Acute Lymphoblastic Leukemia (ALL)
ALL affects lymphoid cells and grows quickly. It accounts for more than 5,000 new cases of leukemia each year. ALL is the most common type of leukemia in young children. It also affects adults.

Acute Myeloid Leukemia (AML)
A rapidly progressing cancer of the blood affecting immature cells of the bone marrow, usually of the white cell population. AML affects myeloid cells and grows quickly. It accounts for more than 13,000 new cases of leukemia each year. It occurs in both adults and children.

Acute Non-Lymphocytic Leukemia
see acute myeloid leukemia

Acute Promyelocytic Leukemia
This is one form of acute myeloid leukemia. It is an aggressive (fast-growing) type of acute myeloid leukemia in which there are too many immature blood-forming cells in the blood and bone marrow. It is usually marked by an exchange of parts of chromosomes 15 and 17. Also called acute promyelocytic leukemia and promyelocytic leukemia.

Agnogenic myeloid metaplasia
A progressive, chronic disease in which the bone marrow is replaced by fibrous tissue and blood is made in organs such as the liver and the spleen, instead of in the bone marrow. This disease is marked by an enlarged spleen and progressive anemia. Also called chronic idiopathic myelofibrosis, idiopathic myelofibrosis, myelosclerosis with myeloid metaplasia, and primary myelofibrosis.

Alkylating Agents
Anti-leukemic drugs which interact with genetic material (DNA) in such a way as to prevent division of the cells. Drugs of this type include busulphan, chlorambucil, cyclophosphamide, dacarbazine, and melphalan. See also chemotherapy.

Allogeneic Bone Marrow Transplant
A bone marrow transplant using marrow collected from a "matched" healthy donor, usually a brother or sister. Most times, the donor must at least partly match you genetically. Special blood tests are done to determine if a donor is a good match for you. However, sometimes parents, children, and other relatives may be good matches. Donors who are not related to you may be found through national bone marrow registries.

see allogeneic bone marrow transplant

The loss of hair. A side effect of some forms of chemotherapy or radiotherapy used to treat leukemia and other cancers. Usually temporary.

Amyloidosis is not a specific disease but the term for a group of conditions in which an abnormal substance called amyloid is deposited throughout the body. Amyloid is produced by plasma cells and amyloidoisis may occur in association with multiple myeloma.

Deficiency the oxygen-carrying pigment hemoglobin in the blood. Causes pallor, tiredness and breathlessness.

Loss of appetite

Drugs, which are used in leukemia therapy to prevent cell division by disrupting the structure of the DNA. Drugs of this type include Daunorubicin, Doxorubicin (Adriamycin), Epirubicin, and Idarubicin. See also chemotherapy.

Drugs, which kill or stop the growth of bacteria, for example penicillin.

Naturally produced substances in the blood, which destroy or neutralize specific toxins or 'foreign bodies', for example viruses. They are produced by the white blood cells known as lymphocytes in response to exposure to antigens.

A drug to prevent or alleviate the nausea and vomiting which sometimes occur as side effects of chemotherapy. Drugs of this type include Metoclopramide (Maxolon), Ondanestron, and Zofran.

A substance which stimulates cells of the body's defense system to react against it by producing antibodies.

Antilymphocyte Globulin
Antibodies, which attach to and destroy lymphocytes. This may be used clinically by injection into a vein, for example in aplastic anemia. One form, called antithymocyte globulin, acts specifically against T-Cells.

A group of anti-cancer drugs which prevent cells growing and dividing by blocking the chemical reactions required in the cell to produce DNA. Drugs of this type include 6 mercaptopurine, azathioprine, thioguanine, and methotrexate. See also chemotherapy.

Failure of production of blood cells in the bone marrow. Usually this condition affects all types of blood cells, which is called aplastic anemia.

Aplastic Anemia
A rare disorder characterized by the failure of the bone marrow to produce blood cells. It may occur as an inherited condition (see Fanconi's anemia) or, more often, the disease develops later in life. This is called acquired aplastic anemia. It leads to a severe shortage of all types of blood cell causing tiredness, susceptibility to infection and serious problems with bleeding.

see autologous bone marrow transplant

Autoimmune Disease
Diseases caused by an individual's immune system producing antibodies against tissues of its own body.

Autoimmune Thrombocytopenia Purpura
see idiopathic thrombocytopenia purpura

Autologous Bone Marrow Transplant (ABMT)
A bone marrow transplant using the patient's own bone marrow or peripheral blood stem cells, which have been collected and stored at an early stage of disease. The marrow may be manipulated in the laboratory (see purging) to try and ensure there is no risk of contamination with leukemia cells.




B Lymphocyte
A type of white blood cell normally involved in the production of antibodies to combat infection.

Microscopic organisms which cause many types of infectious disease, for example pneumonia. Patients have a reduced ability to fight infections following chemotherapy or bone marrow transplantation. This may mean that even normally harmless bacteria, for example those that are normally found on the skin, may cause serious illness.

A type of white blood cells, which is involved in allergic and inflammatory reactions. Normally present in low numbers in the blood.

An increase in the number of basophils in the blood.

Bence-Jones Protein
A characteristic protein found in the urine of most patients with multiple myeloma. It is derived from the antibodies produced by the cancerous myeloma cells and can be used to help in diagnosis of the disease and to monitor the effects of treatment.

Non-cancerous growths that may or may not need to be surgically removed.

A small sample of fresh tissue, for example lymph node or bone marrow, removed for laboratory analysis to establish or confirm an exact diagnosis of disease.

A group of drugs used in multiple myeloma, which do not affect the disease directly but reduce the bone damage and associated pain.

Blast Cells
Immature blood forming cells which normally represent up to 5% of the cells in the bone marrow. They are rarely seen in healthy blood. Acute leukemia is characterized by over-production of abnormal blast cells, which take over the bone marrow and often spill out into the blood stream.

Blast Crisis
Aggressive phase of chronic myeloid leukemia characterized by the production of large numbers of immature cells which may be either of the myeloid or lymphoid type. Clinically similar to acute leukemia and more difficult to treat than chronic phase disease.

Blood Cells
There are three main types of cells in the blood stream; the red cells, which carry oxygen, the white cells, which fight infections, and the PLATELETS, which help prevent bleeding. The correct balance between each cell type must be maintained. Natural chemicals called growth factors, which may be used in treatment, control production of blood cells.

Blood Count
A routine test requiring a small blood sample to estimate the number and types of cells circulating in the blood.

Bone Marrow
The tissue which produces the blood cells and is found within the hollow cavities of many of the bones of the body. Bone marrow contains the stem cells from which all blood cells are derived. Examination of the bone marrow is an important part of the diagnosis of leukemia and the monitoring of treatment.

Bone Marrow Aspirate
A small volume of bone marrow removed under local or general anesthetic from either the hip bone (pelvis) or breast bone (sternum). The cells in the sample can then be examined under the microscope to identify any abnormality in the developing blood cells. A trephine biopsy may be taken at the same time.

Bone Marrow Transplant (BMT)
A procedure used in the treatment of a variety of blood disorders including leukemia, lymphoma and sometimes myeloma. The patient receives very high doses of chemotherapy and/or radiotherapy to treat the disease. This damages the bone marrow and makes the blood cell count fall. Replacement marrow is taken from a matched donor (allogeneic bone marrow transplant) or from the patient themselves (autologous bone marrow transplant) under a general anesthetic and returned to the patient through a vein (or central venous line) in a similar way to a blood transfusion. peripheral blood stem cells may be used instead, especially for autografts.

Burkitt's Lymphoma
An aggressive (fast-growing) type of B-cell non-Hodgkin’s lymphoma that occurs most often in children and young adults. The disease may affect the jaw, central nervous system, bowel, kidneys, ovaries, or other organs. There are three main types of Burkitt lymphoma (sporadic, endemic, and immunodeficiency related). Sporadic Burkitt lymphoma occurs throughout the world, and endemic Burkitt lymphoma occurs in Africa. Immunodeficiency-related Burkitt lymphoma is most often seen in AIDS patients.



Diseases due to the uncontrolled growth and division of cells; often-called malignant disease or neoplasia.

A type of fungus, candida infection in the mouth (oral thrush) is a common problem for immunosuppressed patients.

A tube for insertion into the body, usually into a vein, via a sharp needle-type fitting which is then withdrawn from the cannula to allow fluids to pass through the tube.

A substance, which has the ability to cause cells to become cancerous.

The process by which normal cells are transformed into cancer cells.

Cat Scan (CT SCAN)
Computer Assisted Tomography (CAT) is a sophisticated x-ray technique used to produce detailed internal images of the body, particularly the chest and abdomen. The patient lies on a couch which gradually moves through the X-ray machine and the image is built up by a computer as a cross section through the body.

A hollow tube inserted into organs of the body for admitting or removing gases or liquids. For example, for the removal of urine from the bladder.

Cell Biology
The study of the structure, composition and function of cells.

Cell Markers
Biochemical or genetic characteristics, which distinguish and discriminate between different, cell types. HLA antigens are one type of cell marker.

The individual units from which tissues of the body are formed.

Central Nervous System (CNS)
The brain and spinal cord.

Central Venous Line
A catheter passed through a blood vessel into a large central vein, these are used for patients undergoing intensive therapy and provide a route for taking blood samples and administering drugs without repeated needle puncture of a vein. "HICKMAN"® catheter and portacath. "HICKMAN"® is a registered trademark of C.R. Bard, Inc. and its related company, BCR, Inc.

Treatment using anti-cancer drugs. These may be used singly or in combination to kill or prevent the growth and division of cells. Although aimed at the cancer cells, chemotherapy will also unavoidably affect rapidly dividing normal cells such as in the hair and gut causing hair loss and nausea, which are usually temporary and reversible.

Chromosomes carry the 100,000 genes which provide the inherited blueprint of each individual. In humans there are normally 23 pairs contained in the nucleus of each cell. Alterations in the number or organization of the chromosomes may play a key role in the development of cancer.

Chronic Leukemia
A cancer of the blood of gradual onset and generally of slow progression. May be diagnosed by chance following a routine blood test and prior to the appearance of clinical symptoms.

Chronic Granulocytic Leukemia (CGL)
see Chronic Myeloid Leukemia.

Chronic Lymphocytic Leukemia (CLL)
A slowly progressing form of leukemia, characterized by an increased number of the type of white blood cells known as lymphocytes. It has variable symptoms and course, but may be diagnosed by chance before the patient develops any clinical symptoms of disease.

Chronic Myeloid Leukemia (CML)
A leukemia which is initially slowly progressing. It is characterized by the presence of large numbers of abnormal, mature granulocytes, circulating in the blood. Sometimes called chronic granulocytic leukemia (CGL).

Chronic Myelomonocytic Leukemia (CMML)
A slowly progressing type of myelodysplastic/myeloproliferative disease in which too many myelomonocytes (a type of white blood cell) are in the bone marrow, crowding out other normal blood cells, such as other white blood cells, red blood cells, and platelets. Also called chronic myelomonocytic leukemia.

Clinical Trial
A carefully monitored assessment of new forms of treatment. They can vary in design and size from trials of experimental treatments involving small numbers of patients to large national trials, which compare variations in current therapies. A patient will always be informed when the treatment is part of a trial.

A population of genetically identical cells arising from a single parent cell. Leukemia cells originate from one original abnormal cell producing a "leukemic clone".

Clotting Factors
A group of chemical constituents of the blood (factors I to XIII), which interact to make the blood clot.

CNS Leukemia
Invasion of the brain or spinal cord by leukemic cells. This may be diagnosed by examination of the surrounding cerebrospinal fluid.

Clotting of the blood. A complex reaction depending on a series of biochemical components and platelets in the blood. See clotting factors.

"Common" Acute Lymphoblastic Leukemia (CALL)
A sub-type of acute lymphoblastic leukemia affecting cells early in the B lymphocyte lineage, which accounts for about 80% of all cases of acute lymphoblastic leukemia.

A term used to describe deformities or diseases, which are present at the time of birth.

Consolidation Treatment
A course of treatment with anti-cancer drugs given to the patient whilst in remission with the aim of killing any remaining cancerous cells.

Cord Blood
Blood from the umbilical cord of a newborn baby. This blood contains high concentrations of stem cells (cells from which all blood cells develop).

Cord Blood Stem Cells
Stem cells recovered from cord blood, which have been shown to have the capability to repopulate bone marrow and produce blood cells.

Corticosteroids (steroids)
A group of synthetic hormones including prednisone, prednisolone, methylprednisolone and dexamethasone used in the treatment of some leukemia's and myeloma. Also used to suppress graft rejection and graft versus host disease following bone marrow transplant. Side effects include an increased risk of infection.

Cutaneous T-Cell Lymphoma
Any of a group of T-cell non-Hodgkin lymphomas that begins in the skin as an itchy, red rash that can thicken or form a tumor. The most common types are mycosis fungoides and Sézary syndrome.

Cyclosporine A
A drug used to prevent and treat rejection and graft versus host disease in transplant patients by suppressing their normal immune system.

The study of the structure of chromosomes. Cytogenetic tests are carried out on samples of blood and bone marrow taken from leukemia patients to detect any chromosomal abnormalities associated with the disease. These help in the diagnosis and selection of optimal treatment.

A virus, which is harmless in healthy people but may cause serious disease in severely immunosuppressed patients. Particularly dangerous following a bone marrow transplant.

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

Cytotoxic Drugs
Anti-cancer drugs which act by killing or preventing the division of cells. See chemotherapy.



A chromosome abnormality in which part of a single chromosome has been lost.

A laboratory procedure for reducing the numbers of specific cell types within bone marrow donated for transplantation, for example the removal of some types of lymphocytes. This may be to avoid "mismatch" problems (particularly in relation to unrelated donor transplants) or to remove a sub-set of potentially leukemic cells in an autograft.

The gradual maturation of a cell whereby its functions and properties become increasingly specialized. Leukemic cells are often poorly differentiated, i.e. they show immature characteristics.

Diffuse Large B-cell Lymphoma
A type of B-cell non-Hodgkin lymphoma (cancer of the immune system) that is usually aggressive (fast-growing). It is the most common type of non-Hodgkin lymphoma, and is marked by rapidly growing tumors in the lymph nodes, spleen, liver, bone marrow, or other organs. Other symptoms include fever, night sweats, and weight loss. There are several subtypes of diffuse large B-cell lymphoma.

Disseminated Disease
Disease in which the cancerous cells have spread from the tissue of origin to other organs.

A drug to stimulate the excretion of urine by the kidneys. May be used during chemotherapy to ensure the excretion of anti-cancer drugs.

DNA (Deoxyribonucleic acid)
Provides the essential building block for storing genetic material. There are 4 different chemical components of DNA (bases) arranged in coded sequence as genes, which determine an individual's inherited characteristics.

Donor Lymphocyte Infusion
If a patient who has had an allogeneic bone marrow transplant has a relapse, with return of the original disease, they may be given lymphocytes from the donor. This may eliminate the leukemia cells.

Down's Syndrome
A congenital condition in which some or all of the body cells have three copies of chromosome 21. This form of TRISOMY is associated with an increased risk of leukemia.



A type of white blood cell involved in inflammatory, allergic or anti-parasitic responses. Usually present in the circulation in very low numbers.

Increased numbers of eosinophils circulating in the blood. It occurs in some cases of Hodgkin's disease, in asthma, hay fever and parasitic infections, hypereosinophilic syndrome and eosinophil leukemia.

Eosinophil Leukemia
Some patients with high eosinophil counts and abnormal bone marrow are classed as having eosinophil leukemia. It may not always be obvious whether the diagnosis should be eosinophil leukemia or hypereosinophilic syndrome. Some doctors consider eosinophil leukemia to be a form of chronic myeloid leukemia (CML).

The science of studying the occurrence of disease in populations and relating this to genetic and/or environmental causes.

Epstein Barr Virus (EBV)
A common virus, which causes glandular fever. Also associated with Burkitt's lymphoma. There is some evidence of a link between Epstein-Barr virus infection and Hodgkin's disease.

see red blood cells

Cancer of the blood-forming tissues in which large numbers of immature, abnormal red blood cells are found in the blood and bone marrow.

Essential Thrombocythemia
An increased number of thrombocytes (platelets) in the blood, without a known cause. Also called essential thrombocytosis.

The scientific study of the factors, which cause disease e.g. environmental factors such as infections and radiation.

Extra Nodal Lymphoma
Literally "outside the lymph nodes", but exhibiting the characteristics of lymph node cancer. A term used to describe the extent and site of disease.



Fanconi Anemia
A rare inherited disorder in which the bone marrow does not make blood cells. It is usually diagnosed in children between 2 and 15 years old. Symptoms include frequent infections, easy bleeding, and extreme tiredness. People with Fanconi anemia may have a small skeleton and brown spots on the skin. They also have an increased risk of developing certain types of cancer.

Folic Acid
A form of vitamin B obtained from green leafy vegetables, e.g. spinach. It is essential for synthesis of DNA and therefore the growth and division of cells.

Folic Acid Antagonist
A chemical, which inhibits a cell's capacity to use folic acid and so, prevent cell division, for example methotrexate. See also chemotherapy.

Follicular Lymphoma
A type of B-cell non-Hodgkin lymphoma (cancer of the immune system) that is usually indolent (slow-growing). The tumor cells grow as groups to form nodules. There are several subtypes of follicular lymphoma.

An infective agent such as a mould or yeast, causing particular problems in immunosuppressed patients. See candida.



Gamma Globulin
A concentrated solution of antibodies given through a vein to fight infections, e.g. measles in patients with low resistance.

Normally the gamma globulins, which make up antibodies, are a mixture of a huge number of different types. When nearly all gamma globulin being produced is one particular form this is called monoclonal gammopathy.

Formed from DNA and carried on the chromosome, genes direct the activities of cells. They are responsible for the inherited characteristics, which distinguish one individual from another. Each human individual has an estimated 100,000 separate genes.

Graft Rejection
Rarely, when a patient has an allogeneic bone marrow transplant, the new bone marrow will fail to start producing blood cells. This is called graft rejection. It may be possible to do a second transplant.

Graft Versus Host Disease (GVHD)
A common, and serious, complication of bone marrow transplantation. Some of the donor's immune cells reject the patient's own cells as foreign. The skin, liver and gut may be affected. It can occur in either chronic or acute forms and is treatable by immunosuppressive drugs.

Graft Versus Leukemia (GVL)
If graft versus host disease is present but not severe it may be beneficial in helping to kill off leukemia cells. If all the T-lymphocytes are removed from an allogeneic bone marrow transplant it minimizes the risk of graft versus host disease but increases the risk of relapse.

A type of white cells. They protect the body against infection by seeking out and killing microorganisms.

Growth Factors
A complex family of proteins produced by the body to control growth, division and maturation of blood cells by the bone marrow. Some are available as products of genetic engineering, and are used clinically to stimulate normal white cell production following chemotherapy or bone marrow transplantation.

Growth Hormone
A biochemical secreted by a gland in the brain, which controls growth and is of particular importance during adolescence. Radiotherapy given to the head and neck of children with leukemia may lead to a deficiency in growth hormone. This may be replaced by intravenous injections.



The amount of whole blood that is made up of red blood cells. It depends on the number and size of red blood cells. A hematocrit test is usually part of a complete blood count (CBC). It may be used to check for conditions such as anemia, dehydration, malnutrition, and leukemia. Also called HCT. See also packed cell volume.

A doctor specializing in the diagnosis and treatment of blood diseases.

The study of blood diseases including leukemia.

Term to describe the production and maturation of blood cells from very primitive stem cells. This takes place in the bone marrow, which is a spongy tissue in the middle of bones.

The iron containing pigment in red blood cells, which carries oxygen around the body. Lack of hemoglobin is called anemia. Normal values are between 12-18 grams per 100 ml of blood.

Hemophagocytic lymphohistiocytosis (HLH)
A rare disorder in which histiocytes and lymphocytes (types of white blood cells) build up in organs including the skin, spleen, and liver, and destroy other blood cells. HLH may be inherited or caused by certain conditions or diseases, including infections, immunodeficiency (inability of the body to fight infections), and cancer. Also called hemophagocytic lymphohistiocytosis.
see hematopoiesis

Bleeding either to the outside through the skin or internally.

Hairy Cell Leukemia
A rare type of leukemia in which abnormal B-lymphocytes (a type of white blood cell) are present in the bone marrow, spleen, and peripheral blood. When viewed under a microscope, these cells appear to be covered with tiny hair-like projections.

Inflammation of the liver.

Enlargement of the liver.

"HICKMAN"® Catheter
A narrow plastic tube or catheter, which is inserted, under anesthetic, into a major blood vessel in the chest. It is used for patients undergoing intensive therapy and provides a route for taking blood samples and administering drugs without repeated needle puncture of a vein. "HICKMAN"® is a registered trademark of C.R. Bard, Inc. and its related company, BCR, Inc.

Histiocytosis is a general name for a group of syndromes that involve an abnormal increase in the number of immune cells called histiocytes. Histiocytes are cells produced in the bone marrow and assist in recognizing invading bacteria and parasites. Histiocytes are normally found in skin, liver, lung, gut, lymphatic glands, spleen, bones and parts of the brain but in histiocytosis they wander elsewhere in the body.

The investigation of tissue samples by chemical and microscopical analysis.

HLA Antigens
A complex family of genetically inherited proteins, which are found on the surface of cells throughout the body. They determine the "match" between patient and potential donor in bone marrow transplantation. HLA factors are inherited from the mother and father and so the greatest chance of having the same HLA type is between brothers and sisters that is 1 in 4.

Hodgkin's Disease
A cancer of the immune system that is marked by the presence of a type of cell called the Reed-Sternberg cell. The two major types of Hodgkin disease are classical Hodgkin lymphoma and nodular lymphocyte-predominant Hodgkin lymphoma. Symptoms include the painless enlargement of lymph nodes, spleen, or other immune tissue. Other symptoms include fever, weight loss, fatigue, or night sweats. Also called Hodgkin lymphoma.

Human T cell Lymphotropic virus. A family of viruses, which invade T cells. Includes a rare leukemia virus, HTLV-1, found primarily in Japan and the Caribbean causing an increased incidence of T cell leukemia's in these populations. The family also includes the AIDS causing-virus, HIV.

Increased levels of calcium in the blood. It is often associated with multiple myeloma due to degradation of the bones. It is dangerous if not controlled.

Hypersinophilic Syndrome
In some patients the number of eosinophils in the blood is markedly and persistently raised with no obvious cause such as a parasite infection. These patients have either hypereosinophilic syndrome (HES) or eosinophil leukemia.



Iatrogenic Disease
A disease produced as a consequence of medical or surgical treatment.

Term applied to diseases to indicate that their cause is unknown.

Idiopathic myelofibrosis
See agnogenic myeloid metaplasia

Idiopathic Thrombocythenia Purpura (ITP)
A rare disorder characterized by an acute shortage of platelets with resultant bruising and spontaneous bleeding. Anti-platelet antibodies are detectable in some cases. It may present in either an acute or a chronic form.

Immune Deficiency
Impaired ability of the body's defense mechanisms to combat infections by bacteria, viruses and fungi.

Immune Response
The reaction of the body to an antigen, for example an infectious agent, or to the tissues of another individual as in the rejection of an organ transplants.

Proteins in the blood PLASMA, which function as antibodies and play an important part in controlling infections.

A treatment induced reduction in the body's defense mechanisms. Deliberate immunosuppression is a necessary part of the bone marrow transplant procedure to prevent graft versus host disease and graft rejection.

Induction Treatment
see remission induction

Increasing the amount, number or combination of anti-cancer drugs given to a patient in an attempt to kill drug-resistant or residual leukemic cells.

A family of proteins derived from human cells and involved in fighting viral infections. They are now available as products of genetic engineering for use in the treatment of a number of leukemias and leukemia-related diseases including hairy cell leukemia, chronic myeloid leukemia and aplastic anemia.

Intramuscular Injection
Injection into the muscle.

Intrathecal Injection
Injection of drugs into the spinal fluid to prevent or treat CNS leukemia or lymphoma.

Intravenous Infusion
The giving of antibiotics, blood products, anti-cancer drugs or nutrients into a patient's vein over a prolonged period of time.

Intravenous Injection
The giving of drugs into a vein through a syringe.

In Vitro
Literally meaning "in glass". Used to describe studies carried out on living cells or tissues grown in the laboratory.

In Vivo
In living tissue or in a whole organism.



Juvenile Myelomonocytic Leukemia (JMML)
A rare form of childhood leukemia in which cancer cells often spread into tissues such as the skin, lung, and intestines.



Analysis to check the number, form and structure of chromosomes. This can give valuable information to aid in the diagnosis and the selection of treatment.

Karyotypic Abnormality
Abnormality in the number, form or structure of chromosomes. Particular abnormalities are associated with particular sub-types of leukemia.



Large Granular Lymphocytic Leukemia
Large granular lymphocytic leukemia (LGL) is a chronic leukemia, which affects T-cells. LGL is a rare disease with important clinical differences from chronic lymphocytic leukemia.

Late Effects
Results of chemotherapy and/or radiotherapy, which only become apparent with long-term monitoring of the patient over a period of years. These are of particular concern in patients below the age of puberty.

From the Greek meaning, "white blood". Often referred to as cancer of the blood. Characterized by the widespread uncontrolled proliferation of large numbers of abnormal blood cells, usually of the white cell lineages, which take over the bone marrow and often spill out into the blood stream. Other organs that may also be affected include lymph nodes, spleen, and liver.

The development of leukemia.

Method of separating blood into its liquid and cellular components and for the removal of white blood cells before returning the remainder of the blood to the patient. It is used to reduce the white cell count when chemotherapy is to be avoided, for example during pregnancy.

Collective term for white blood cells.

Condition in which the number of white cells in the blood is greatly reduced. Leads to increased risk of infections.

Describes cells with a common ancestry that is developing from the same type of identifiable immature cell.

Li-Fraumeni Syndrome
A rare, inherited predisposition to multiple cancers, caused by an alteration in the p53 tumor suppressor gene.

Long-term Survival
Term used to describe the survival of leukemia patients who have been disease free for prolonged periods of time, usually at least five years. The chance of disease returning (relapse) decreases with time.

Lumbar Puncture
A procedure for removing spinal fluid from around the spinal cord using a fine needle in the lower part of the back. Samples are analyzed for evidence of any CNS leukemia. Also used to administer anti-cancer drugs to either prevent or cure CNS disease.

Lymph Nodes or Glands
Small structures found throughout the body, e.g. neck, groin, armpits, abdomen, which contain both mature and immature lymphocytes.

Lymphatic System
This consists of the spleen, lymph nodes and areas of lymphoid tissue such as the tonsils. It plays a major part of the body's immune response.

A type of white blood cell, which is involved in the immune defenses of the body. There are two main types - B-cells and T-cells.

Referring to the lymphatic system including lymphocytes and lymph nodes.

A cancer, which originates in lymphoid tissue, including the lymph glands, liver, spleen, bowel and bone marrow. The disease results from the uncontrolled production of lymphocytes. The general term includes about a dozen different forms of the disease but there are two main categories: Hodgkin's disease and non-Hodgkin's lymphoma.

Lymphoplasmacytic Lymphoma
See Waldenstrom's Macroglobulinemia

An increase in the production of lymphocytes. This may occur as a normal response to infection.



A condition in which the blood contains high levels of large proteins and is too thick to flow through small blood vessels. In certain conditions, such as Waldenstrom's Macroglobulinaemia, affected lymphocytes produce an excess amount of an abnormal antibody known as IgM for Macroglobulin.

A type of white blood cell which migrates from the blood into tissues and acts as a scavenger, ingesting particles such as bacteria.

Magnetic Resonance Imaging
A body scanning technique, which uses an intense magnetic field to generate images of the internal organs. Properties of normal and cancerous tissue differ, allowing malignant tumors to be visualized by computer processing of the signals detected.

Maintenance Treatment
Treatment given for a period of months or years to maintain remission and eliminate any residual leukemic cells in the body, usually for acute lymphoblastic leukemia.

A term applied to tumors characterized by the uncontrolled proliferation of cells. See also cancer.

Mantle Cell Lymphoma
An aggressive (fast-growing) type of B-cell non-Hodgkin lymphoma that usually occurs in middle-aged or older adults. It is marked by small- to medium-size cancer cells that may be in the lymph nodes, spleen, bone marrow, blood, and gastrointestinal system.

Mast Cell Leukemia
The mast cell is related to the monocyte/macrophage cells of the immune system and is found in most tissues. Excessive production of mast cells may be seen in the conditions systemic mastocytosis and mast cell leukemia.

Large cell in the bone marrow, which produce platelets.

Proteins made by cells which all belong to the same clone are identical and are called monoclonal.

Monoclonal Antibodies
Antibodies made by cells belonging to a single clone. Current research is investigating their clinical application for targeted delivery of drugs to leukemic cells and to purify cells used for bone marrow and stem cell transplants.

Monoclonal Gammopathy Of Unknown Significance
Different types of gamma globulin are produced to deal with different infections. Exclusive production of one form of gamma globulin is called monoclonal gammopathy. If there is no evidence of disease such as myeloma or lymphoma to explain the presence of a monoclonal gammopathy it is called Monoclonal Gammopathy of Unknown Significance (MGUS).

A type of white blood cell of relatively large size, which acts as a scavenger and ingests large particles.

Monocytic Leukemia
Cancer of the blood due to proliferation of cells of the monocyte series.

Term which indicates the loss of a whole chromosome.

MRC (Medical Research Council)
Government funded body "to promote the balanced development of medical and related biological research" in the UK. It organizes national clinical trials for the assessment of new treatment protocols for leukemia and some of the related diseases.

Inflammation of the mouth and throat, which may be caused by anti-leukemia drugs.

Multi-drug Resistance
Multi-drug resistance occurs when leukemia cells eliminate anti-cancer drugs before a high enough concentration to kill the cells is achieved. Resistance against most drugs will make the leukemia very difficult to treat.

Multiple Myeloma
A cancer caused by uncontrolled proliferation of the white blood cells called plasma cells within the bone marrow. The malignant cells do not usually accumulate in the blood and the tumor growth is restricted to the bones. This leads to bone destruction and is often associated with kidney problems.

A minute genetic change to DNA, for example by exposure to hazardous chemicals or copying errors during cell division. If these affect normal cell function it can lead to disease development.

Immature cells of the myeloid series.

Myelodysplasia Or Myelodysplastic Syndromes (MDS)
One of a group of cancers in which there are more abnormal cells than normal healthy blood cells (white blood cells, red blood cells, and platelets) in the bone marrow or blood. When there are fewer blood cells, infection, anemia, or bleeding may occur. Sometimes, myelodysplastic syndrome becomes acute myeloid leukemia (AML). Also called MDS.

A disease in which the bone marrow is taken over by fibrous tissue and is no longer able to produce adequate numbers of mature blood cells. Often accompanied by enlargement of the spleen. It is occasionally found in cases of acute myeloid /acute lymphoid /chronic myeloid leukemia. The primary form is classified as a myeloproliferative disorder.

Collective term for the non-lymphocyte groups of white blood cells. It includes cells from the granulocyte, monocyte and platelets lineages.

A condition, which affects both the myeloid and monocyte cells.

The process of production and maturation of myeloid cells. See hematopoiesis.

Myeloproliferative Disorders
A group of disorders characterized by the over- production of blood cells by the bone marrow. One or more of the cell lineages may be involved and treatment varies according to the type and severity of the disease. See essential thrombocythaemia, polycythaemia rubra vera.

see myelofibrosis



Damage to the nerves, which may occur as a complication of anti-leukemia treatment. It usually affects the peripheral nerves (nerves to the arms and legs) and may be reversible when treatment is stopped or reduced.

A condition in which the neutrophil count is reduced. It may be caused by high dose chemotherapy and carries an increased risk of infection.

The most common type of cell within the granulocyte group of white blood cells.

Non-Hodgkin's Lymphoma
A group of lymphomas, which differ in important ways from Hodgkin's disease and are, classified according to the microscopic appearance of the cancer cells. The disease is classified as either indolent (slowly growing) or aggressive (rapidly growing) and may be treated in a variety of ways depending on the exact diagnosis.



Genes carrying the potential to cause cancer.

A specialist in the diagnosis and treatment of cancer.



Packed Cell Volume
Measurement of the proportion of the blood occupied by the red blood cells. Normal values are 40-54% in males, 35-47% in females.

Palliative Care
Treatment aimed at relieving symptoms and pain rather than affecting a cure. Pancytopaenia Condition in which there are reduced numbers of all types of blood cells.

Paraprotein (malignant)
Malignant paraprotein is a form of antibody characteristic of, and produced by, malignant cells of the mature B-cell type, for example in multiple myeloma. Its presence in the blood acts as an important marker of disease.

Paroxysmal Nocturnal Haemoglobinuria (PNH)
A rare disorder characterized by an increased rate of break- down of red blood cells and decreased production of white blood cells and platelets. This leads to excretion of the red blood pigment, hemoglobin, in the urine, particularly at night. The cause is unknown and the severity of disease variable.

Development of a disease.

A doctor who specializes in the cause and diagnosis of disease and how disease affects the organs of a body.

Peripheral Blood Stem Cell
There are small numbers of stem cells in the circulation. These are known as Peripheral Blood Stem Cells. (PBSC)

Peripheral Blood Stem Cell Transplant
The use of peripheral blood stem cells as an alternative to bone marrow transplantation. The stem cells are obtained by using growth factors to increase numbers in the circulation to a level where they can be harvested.

Small red or purple pinhead spots on the skin. They are small hemorrhages and usually the result of a shortage of platelets.

The study of the action of a drug in the body over a period of time, including the processes of absorption, metabolism and excretion.

The characteristic appearance and function of a cell or tissue.

Philadelphia Chromosome
An abnormal chromosome associated with chronic myeloid leukemia and some cases of acute lymphoblastic leukemia. The Philadelphia chromosome is formed when part of chromosome 9 attaches to chromosome 22. This abnormality is found in nearly all cases of chronic myeloid leukemia.

Plasma Cells
Large cells derived from the lymphocytes that form antibodies. Not normally found in circulating blood but restricted to bone marrow and lymph nodes.

Plasma Cell Leukemia
The end stage of myeloma when immature plasma cells are found circulating in the blood.

A localized area of myeloma-like disease, either in a bone or in the other tissues of the body. If there is only one such area it is called solitary plasmacytoma.

Plateau Phase
Stable stage of disease in lymphoma following good response to anti-cancer treatment.

Tiny cell-like bodies derived from megakaryocytes in the bone marrow. Circulate in the blood and play an important role part in the prevention and control of bleeding. Normal values, 150-400 x 109 per liter.

Polycythaemia Rubra Vera (PRV)
A condition characterized by the over-production of red blood cells by the bone marrow. Diagnosis is based on an increased number and volume of red cells. The total number of white blood cells and platelets may also be increased. Treatment will vary according to the age of the patient and severity of the disease. This condition carries an increased risk of developing acute leukemia.

A form of central venous line in which the whole of the line is surgically implanted within the body, unlike a "HICKMAN"® catheter. A membrane just below the skin gives access by a simple skin puncture to a line running straight into one of the main blood vessels. This simplifies the administration of chemotherapy. "HICKMAN"® is a registered trademark of C.R. Bard, Inc. and its related company, BCR, Inc.

A general term referring to some non-cancerous blood disorders, such as myelodysplasia, which carry an increased risk of the patient developing acute leukemia. The expression is misleading because only a minority of patients with these conditions develops leukemia.

Progenitor Cell or Precursor Cell
Immature cell in the bone marrow, which is responsible for producing mature blood cells.

An assessment of the likely benefits of treatment for a patient, particularly concerning the chances of cure and complete recovery.

An early lymphocyte precursor. Not commonly seen in the blood but in prolymphocytic leukemia they may be present in large numbers.

Prolymphocytic Leukemia (PLL)
A variant of chronic lymphocytic leukemia in which the malignant cells have a more immature appearance. The disease requires chemotherapy and/or radiotherapy and sometimes removal of the spleen (splenectomy).

Precautionary treatment given with the aim of preventing a disease occurring.

A schedule of treatment. For example, the number, frequency and timing of administration of a course of anti-cancer drugs.

Itching, sometimes severe, which may be a significant problem in lymphoma.

The laboratory treatment of bone marrow harvested for an autologous bone marrrow transplant or peripheral blood stem cell transplant to remove any residual leukemic cells in order to reduce the theoretical chance of relapse. The use of this procedure varies between treatment centers and depends on the type of leukemia being treated.

A condition characterized by the occurrence of purple spots on the skin, often accompanied by bleeding from the gums.



The use of x-rays in the diagnosis of a disease.

The use of x-rays and other forms of radiation in treatment. It kills cancer cells in the area of the body being treated and is therefore effective treatment for localized disease, particularly in lymphoma and multiple myeloma. Side effects vary according to the type of treatment and will be discussed with the patient by the hospital staff.

Rai System
A system for classification of chronic lymphocytic leukemia based on the symptoms, if any, and on laboratory tests. It is used to decide whether to start treatment.

A term used to describe drugs, which have been produced using the techniques of genetic engineering. The products are exact equivalents of compounds produced naturally by the body.

Red Blood Cells
The cells of the blood, which contain the red, pigment hemoglobin and carry oxygen to all the tissues of the body. Normal red cell count in the blood, 4.5-5.0 x 1012 per liter.

Reed-Sternberg Cell
A distinctive abnormal cell seen in Hodgkin's disease.

Refractory Anemia
A form of myelodysplasia, which primarily affects red cell production by the bone marrow. In some cases the developing red cells show an internal ring of iron granules. These cells are called sideroblasts. Refractory anemia (RA) and refractory anemia with sideroblasts (RAS) are the most common forms of myelodysplasia.

Refractory Anemia With Excess Blasts (RAEB)
A form of myelodysplasia characterized by the build up of immature white blood cells (blast) in the bone marrow. If the immature cells are particularly numerous it may indicate a chance of transformation to acute leukemia and the condition is called RAEB in transformation (RAEBt).

The recurrence of disease. In leukemia this may be indicated by changes in the blood, bone marrow, CNS or testicle even before the patient experiences any symptoms.

Restoration of the blood, bone marrow and general health of the patient to normal. Induced by chemotherapy and/or radiotherapy.

Remission Induction
The initial course of treatment given to patients on admission to hospital to remove all clinically detectable cancer.

Immature red blood cells normally restricted to the bone marrow and present in the blood stream in very low numbers (0.2-2%). An increase in numbers indicates increased proliferation in the bone marrow, for example following chemotherapy.

Retinoic Acid
A synthetic compound related to vitamin A, which can stimulate cells to become fully mature. It may be used clinically to treat some forms of leukemia, notably a sub-type of acute myeloid leukemia called acute promyelocytic leukemia.

A type of virus that has RNA instead of DNA as its genetic material. A type of virus, which is related to the AIDS virus. One rare form of human leukemia is caused by the HTLV-1 retrovirus.

Richter's Syndrome
Development of lymphoma in a patient who has chronic lymphocytic leukemia.

RNA (Ribonucleic acid)
A copy of the genetic code used by cells as a template for making proteins. It copies the message given out by the DNA.



Secondary Leukemia
A leukemia arising from either previous chemotherapy or radiotherapy or as the development of a pre-existing condition, such as myelodysplasia.

This is a general term to describe serious bacterial infection of the blood stream often associated with high fever.

The part of the blood, which remains after cells, platelets and fibrinogen have been removed, usually by allowing the blood to clot.

Sezary syndrome
A cancer that affects the skin. It is a form of cutaneous T-cell lymphoma.

Brother or sister.

see refractory anemia.

Small Lymphocytic Lymphoma (SLL)
An indolent (slow-growing) type of lymphoma in which too many immature lymphocytes (white blood cells) are found mostly in the lymph nodes. This causes the lymph nodes to become larger than normal. Sometimes cancer cells are found in the blood and bone marrow, and the disease is called chronic lymphocytic leukemia. The disease is most often seen in people older than 50 years. SLL is a type of non-Hodgkin Lymphoma. Also called small lymphocytic lymphoma and well-differentiated lymphocytic lymphoma.

The spleen acts as a "discriminating filter" of the blood. It can selectively remove old red blood cells and bacteria and other foreign bodies. The spleen also acts as a store for platelets. It is often enlarged in leukemia.

Surgical removal of the spleen. This is sometimes done in leukemia or lymphoma as part of a patient's treatment.

Enlargement of the spleen.

An assessment of the spread of disease through the body, for example in lymphoma. It is of importance for the selection of optimal treatment.

Stem Cells
The most primitive cells in the bone marrow from which all the various types of blood cell are derived.

see corticosteroids

Subcutaneous Injection
An injection into tissue immediately under the skin.

Literally "sharing the same genes". It refers to bone marrow or peripheral blood stem cell transplants between identical twins.



T-cell Lymphoma
A type of cancer that forms in T cells (a type of immune system cell). T-cell lymphomas may be either indolent (slow-growing) or aggressive (fast-growing). Most T-cell lymphomas are non-Hodgkin lymphomas.

A type of white blood cell derived from the thymus (hence T cells) involved in controlling immune reactions. Uncontrolled proliferation of this type of cell gives rise to T cell lymphoma/lymphoma.

Testicular Relapse
Recurrence of leukemia in the testicles. The disease may be restricted to the testicles or may also show evidence of disease in either the bone marrow or CNS. Treatment will depend on the timing and extent of relapsed disease.

see platelet

An over-production of platelets. See also essential thrombocythemia.

Shortage of platelets leading to problems with bleeding.

The development of a clot in a blood vessel, usually in a vein but sometimes in an artery. Potentially life-threatening if left untreated.

An organ that is part of the lymphatic system, in which T lymphocytes grow and multiply. The thymus is in the chest behind the breastbone.

An x-ray picture of internal organs of the body.

Total Body Irradiation (TBI)
Radiotherapy often given in several doses prior to bone marrow transplantation with the aim of killing any residual leukemia in the patient. It is used in conjunction with high dose anti-cancer drugs. The procedure and its side effects will be discussed individually with the patient.

A term to describe either the change of a normal cell into a cancerous cell, or the acceleration of disease in chronic myeloid leukemia from the chronic to a more acute phase characterized by the production of large numbers of blast cells.

A chromosome abnormality in which the part of one chromosome has become transferred to another. See also Philadelphia chromosome.

Trephine Biopsy
Removal of a small "core" of bone marrow under local anesthetic. It is used to assess bone marrow structure, the number and distribution of all the blood cell types. The trephine biopsy is normally done at the same time as a bone marrow aspirate.

Term which indicates the presence of an additional whole chromosome.

An accumulation of abnormal cells, which may be benign or malignant.



Ultrasonography (Ultrasound)
Pictures of the body's internal organs built up from the interpretation of reflected sound waves.



Vinca Alkaloids
Anti-cancer drugs originally derived from Vinca (periwinkle) plants. A type of drug that blocks cell growth by stopping mitosis (cell division). Drugs of this type include vincristine, vinblastine. See also chemotherapy.

The study of viruses and viral diseases.

A minute infective agent, which depends on the cell, it infects for its replication and survival.



Waldenstrom's Macroglobulinemia
rare disorder, which has features in common with an indolent non-Hodgkin's lymphoma and with multiple myeloma. The progression of the condition more closely resembles indolent non-Hodgkin's lymphoma.

White Blood Cells (Leukocytes)
They comprise several different types of cells within three main types: granulocytes, lymphocytes and monocytes. They are formed in the bone marrow and it is their uncontrolled proliferation, which leads to leukemia.



X Rays
A form of radiation used both in diagnosis, for example staging of lymphoma and multiple myeloma, and treatment (see radiotherapy).



Zig (Zoster Immune Globulin)
Gamma globulin against the chicken pox virus, which can be given to an immunosuppressed patient following direct contact with the disease to prevent infection.

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