The ANC refers to the number of neutrophils (a type of white cell) that a person has in their blood to fight infection. It is calculated by multiplying the total number of white cells by the percentage of neutrophils.
Alkylating Agent
An Alkylating agent is 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
ASCT is a treatment that uses donor stem cells to restore a patient’s marrow and blood cells. First, the patient is given conditioning therapy (high-dose chemotherapy or high-dose chemotherapy with total body radiation) to treat the blood cancer and to “turn off” the patient’s immune system so that the donor stem cells will not be rejected.
A type of transplant called a “reduced-intensity” or “non-myeloablative” transplant is sometimes used also; the “reduced intensity” transplant uses lower doses of conditioning therapy and may be safer, especially for older patients.
Anaemia
Anaemia is the result of a decrease in the number of red blood cells and, therefore, the haemoglobin concentration of the blood. The decrease in the haemoglobin level in the blood means that the blood is less able to carry oxygen. In severe cases, anaemia can cause a pale complexion, weakness, fatigue and shortness of breath on exertion.
Anthracyclines (Anti-tumour Antibiotics)
Anthracyclines are chemotherapy agents that interact directly with the DNA in the nucleus of cells, thus interfering with cell survival.
Antibodies
Antibodies are proteins released by plasma cells (derived from B lymphocytes) that recognize and bind to specific foreign substances, called “antigens.” Antibodies coat, mark for destruction or inactivate foreign particles such as bacteria, viruses and harmful toxins found in the body.
Antibodies can also be made in the laboratory in two ways. The first way takes advantage of the fact that if material is injected from one species into a different species, the latter will recognize it as foreign and make antibodies to attack it. These antibodies are usually polyclonal antibodies; that is, they react to multiple targets (antigens).
The second way involves monoclonal antibodies, which react to only one target (antigen) and can be used in several important ways. They can be used to identify and classify types of blood cancers or be altered so as to become useful in antibody-mediated immunotherapy.
Antigen
An antigen is a foreign substance, usually a protein, that stimulates an immune response when it is ingested, inhaled or comes into contact with the skin or mucous membranes. Examples of antigens are bacteria, viruses or allergens. Antigens stimulate plasma cells to produce antibodies.
Antimetabolites
Antimetabolites are chemotherapy agents that are generally similar to natural building blocks of DNA, RNA or some vitamins. However, they are changed from the natural chemical. When they substitute for the DNA or RNA building blocks within a leukaemic cell, the cell is unable to form normal DNA or RNA. This prevents the cell from growing.
Antioncogene
See Tumour Suppressor Gene
Apheresis
Apheresis is the process of removing components of a donor’s blood and returning the unneeded parts to the donor. The process, also called “haemapheresis,” circulates blood from a donor through a filter-type apparatus, and then back to the donor. Apheresis makes it possible to remove desired elements from large volumes of blood. Platelets, red cells, white cells and plasma can be removed separately.
For example, this technique permits the harvest of enough platelets for transfusion from one donor (rather than six to eight separate donors). In this way, the recipient of the platelets is exposed to fewer donors or can be given HLA-matched platelets from a single related donor. This technique is also used to remove circulating blood stem cells, which can be frozen and stored for later use in transplantation.
Autologous Stem Cell Transplantation (ASCT)
This is a technique used to delay the progression of certain blood cancers. The autologous transplantation process takes place after the patient achieves a complete response (remission), or a good partial response, to induction drug therapy.
The process is as follows:
the patient’s stem cells are harvested, usually from the blood;
the stem cells are frozen for later use and the patient receives conditioning drug therapy;
the stem cells are thawed and infused back to the patient through an indwelling catheter (central line).
The main adverse side effects of the transplant are the results of the conditioning therapy; these include mouth sores, hair loss, nausea, vomiting, diarrhoea and risk of infections.
Patients receive supportive care to help prevent and/or manage the side effects. Generally, after 10 to 14 days, blood counts begin to normalize and the side effects of the conditioning therapy begin to resolve.
Autosomes
See Karyotype
Basophil
A basophil is a type of white cell that participates in certain allergic reactions.
Biomarkers
Chemicals or structures present either on the surface of or within cells or in the serum. They may aid doctors 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 Acute Myeloid Leukaemia abnormalities in cancer cells. No single feature can accurately predict disease progression in a patient; therefore, doctors use a combination of factors to make a diagnosis and a treatment plan. Biomarkers are also known as “cancer cell markers” and “tumour markers.”
Biopsy
A biopsy procedure is used 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. Since the appearance of a lymph node is important in categorizing the type of lymphoma that may be present, surgical removal of one or more entire, swollen lymph nodes may be necessary (lymph node biopsy). The tissue is placed in preservative, stained with dyes and examined under a microscope by a pathologist.
Blast Cells
These are the earliest marrow cells identified by the light microscope. Blasts represent about 1 per cent of normally developing marrow cells. They are largely myeloblasts, which are cells that will develop into neutrophils. In normal lymph nodes, blasts are lymphoblasts; that is, cells that are part of lymphocyte development. In the acute types of leukaemia, blast cells similar in appearance to normal blast cells accumulate in large numbers, constituting up to 80 per cent of all marrow cells.
In myelodysplastic syndromes and acute myeloid leukaemia, myeloblasts accumulate, and in acute lymphoblastic leukaemia, lymphoblasts accumulate. Normal myeloblasts give rise to granulocytes (neutrophils, eosinophils and basophils). With myelodysplastic syndromes, abnormal myeloblasts displace or otherwise interfere with the production of normal red cells, white cells and platelets in the marrow.
Sometimes the distinction between myeloblasts and lymphoblasts can be made by examination of stained marrow cells through the microscope.
Often, immunophenotyping or use of specially stained marrow cells is required to be sure of the distinction.
Blood Cell Count/Full Blood Count/Complete Blood Count (FBC or CBC)
A laboratory test requiring a small blood sample which can be used to measure the number and types of cells circulating in the blood. The term complete blood count or CBC, or full blood count FBC is often used to refer to this test.
Blood Cells
Any of the three main types of cells in the blood: red cells, which carry oxygen; white cells, which principally prevent or combat infections; and platelets, which help prevent bleeding. There are several types of white cells in the blood. Each cell type is represented in blood in the numbers that meet the functions it serves.
One fluid ounce of blood contains about 150 billion red cells, 8 billion platelets, and 20 million white cells. Red cells live for months, platelets live for a week or two, and white cells live for a few days. The marrow must replace over 500 billion cells from the blood each day.
Blood Plasma
See Plasma.
Bone Marrow
Bone Marrow is a spongy tissue in the hollow central cavity of the bones that is the site of blood cell formation. 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 do not contain blood-forming marrow. In these sites the marrow is filled with fat cells. When marrow cells have matured into blood cells, they enter the blood that passes through the marrow and are carried throughout the body.
Bone Marrow Aspiration
A test to examine marrow cells to detect cell abnormalities. A marrow sample is usually taken from the patient’s hip bone. After medication is given to numb the area, the liquid sample is removed using a special needle inserted through the bone and into the bone marrow. The sample is looked at under a microscope for abnormal cells. The cells obtained can also be used for cytogenetic analysis and other tests.
Bone Marrow Biopsy
This is a test to examine marrow cells to detect cell abnormalities. This test differs from a bone marrow aspiration in that a small amount of bone filled with marrow is removed, usually from the hip bone. After medication is given to numb the area, a special biopsy needle is used to remove a core of bone containing marrow. The marrow is examined under a microscope to determine if abnormal cells are present. Bone marrow aspiration and biopsy may be done in the doctor’s office or in a hospital. The two tests are almost always done together. Both tests are also done after treatment to determine the proportion of blood cancer cells that have been killed by therapy.
CBC
See Blood Cell Count
Central Line
A special tube inserted into a large vein in the upper chest. The central line, sometimes referred to as an “indwelling catheter,” is tunnelled under the skin of the chest to keep it firmly in place. The external end of the catheter can be used to administer medications, fluids or blood products or to withdraw blood samples.
With meticulous care, central lines can remain in place for long periods of time (many months) if necessary. They can be capped and remain in place in patients after they leave the hospital, and be used for outpatient chemotherapy or blood product administration. There are several types of catheters (one example is the Hickman) which can be used for patients receiving intensive chemotherapy or nutritional support.
Central Nervous System (CNS) Prophylaxis
Chemotherapy or radiation therapy given to the central nervous system (CNS) as a preventive treatment. It kills cancer cells that may be in the brain and spinal cord, even though no cancer has been detected there
In certain types of leukaemia, particularly acute lymphocytic (lymphoblastic) leukaemia and acute myeloid leukaemia with high blood cell counts, the leukaemic cells have a tendency 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 leukaemia returns, first in the coverings of the CNS, then in the marrow and blood.
To prevent this type of relapse (meningeal leukaemia), virtually all children and adults with acute lymphocytic leukaemia who enter remission are treated with CNS Acute Myeloid Leukaemia prophylaxis. In some cases, x-ray therapy is administered to the head as well. These approaches are very effective in eliminating leukaemia cells in the meninges.
Chemotherapy
The use of chemicals (drugs or medications) to kill malignant cells. Numerous chemicals have been developed for this purpose, and most act to injure the DNA of the cancer cells. When the DNA is injured, the cells cannot grow or survive.
Successful chemotherapy depends on the fact that malignant cells are somewhat more sensitive to the chemicals than normal cells. Because the cells of the marrow, the gastrointestinal tract, the skin and the hair follicles are most sensitive to these chemicals, injury to these organs causes the common side effects of chemotherapy such as nausea, mouth sores and hair loss.
Chloroma
A solid tumour composed of immature granulocytes, including blast cells. Chloroma’s tend to occur in the brain or spinal cord and the 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. Chloroma’s are an uncommon complication of AML. Other terms for chloroma are “granulocytic sarcoma” and “extramedullary myeloblastoma.”
Chromosome
A chromosome is any of the 46 structures in the nucleus of all cells in the human body
(except the red blood cells) that contain a strand of DNA.
This strand is made up
principally of genes, which are specific stretches of the DNA. “Genome” is the term
for an organism’s complete set of DNA. The human genome has been estimated to
contain about 30,000 genes.
The genes on the X and Y chromosomes are the
determinants of our gender: two X chromosomes produce a female and an X and a Y
chromosome produce a male.
Each chromosome has a long arm (called “q”) and a short
arm (called “p”). The number or size of chromosomes may be altered in blood cancer
cells as a result of chromosome breakage and rearrangement. See Inversion;
Translocation.
Clinical Trials
Clinical trials are carefully planned and monitored research studies, conducted by
doctors. The goal of clinical trials for blood cancers is to improve treatment and
quality of life and to increase survival. A treatment that is proven safe and effective in
a clinical trial is often approved by the United States Food and Drug Administration
(FDA) for use as a standard treatment if it is more effective or has fewer side effects
than the current standard treatment.
Clonal
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. Leukaemia, lymphoma, and myeloma are examples of clonal cancers; that is, cancers derived from a single abnormal cell.
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) and CD52 (the target of the monoclonal antibody therapy Alemtuzumab).
Colony-Stimulating Factor
See Growth Factor
Complete Blood Count
See Blood Cell Count
Conditioning Treatment
This is the 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 (donor tissue). Second, it markedly decreases the number of marrow cells, which may be important to open up the special niches where the transplanted stem cells must lodge to engraft (survive). Third, if the patient is being transplanted for a malignancy, this intensive therapy greatly decreases the numbers of any remaining tumour cells.
Cord Blood Stem Cells
Stem cells that are present in blood drained from the placenta and umbilical cord
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
matched or nearly matched unrelated donors.
Cycle of Treatment
A cycle of treatment is 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
This is the process of analysing the number and size of the chromosomes of cells. In
addition to detecting chromosome alterations, in some cases it is possible to identify
the actual genes that have been affected.
These findings are very helpful in diagnosing
specific types of blood cancers, in determining treatment approaches and in following
the response to treatment. The individual who prepares and examines the
chromosomes and interprets the results is called a cytogeneticist.
Cytopenia
Refers to a reduction in the number of cells circulating in the blood.
Cytotoxic Drugs
Anti-cancer drugs that act by killing cells or preventing them from dividing, see
Chemotherapy.
Deletion
A chromosomal abnormality in which part or all of a single chromosome has been lost
Differentiation
Is the process by which stem cells give rise to functional cells of a single blood cell line; differentiation of stem cells forms red cells, platelets and white cells (neutrophils, monocytes, eosinophils, basophils and lymphocytes).
DNA
The abbreviation for deoxyribonucleic acid, the genetic material in the cell. DNA is
made up of a sugar-phosphate backbone with ladder-like “steps” composed of purines
and pyrimidines (building blocks of nucleic acids). The sequence of the purines and
pyrimidines in the DNA is responsible for passing genetic information to new cells
during the process of cell division; for passing genetic information from one
generation to the next during reproduction; and for providing the instructions for
building proteins, which in turn carry out the major functions of a cell. A mutation is
generally a change in or loss of the sequence of the purines or pyrimidines of the
DNA. Mutations can lead to cell death, to changes in the way a cell functions or, in
some cases, to cancer.
Donor Lymphocyte Infusion (DLI)
A therapy that involves giving lymphocytes from the original stem cell donor to a
patient who has had an allogeneic bone marrow transplant with a relapse of disease. DLI may induce an immune reaction against the patient’s cancer cells. This therapy has been most effective in patients with chronic myeloid leukaemia who relapse after transplantation but this therapy is being studied to treat patients with other blood cancers.
Eosinophil
A type of white cell that participates in allergic reactions and helps fight certain
parasitic infections.
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 – 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.
Erythrocytes
See Red Cells
Erythropoietin (EPO)
A hormone required for the normal production of red blood cells. It is produced mainly
by the kidneys and is released into the blood in response to decreased levels of oxygen
in the blood. Epoetin alfa (Procrit® or Epogen®) and darbepoetin alfa (Aranesp®) are
laboratory-made forms of the human hormone erythropoietin that can be used to treat
anaemia.
In oncology, these drugs are used to assist in the recovery from
chemotherapy-induced anaemia or to treat chronic diseases in which anaemia is a
troublesome finding, such as lower-risk myelodysplastic syndromes. These drugs
stimulate red cell production by the same mechanism as EPO; that is, by interacting
with the EPO receptor on red cell progenitors.
ESR
See Sedimentation Rate
Extramedullary Myeloblastoma
See Chloroma
Farnesyl Transferase Inhibitor (FTI)
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 some blood cancers.
FDA
The acronym for the United States 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.
FISH
See Fluorescent In Situ Hybridization
Flow Cytometry
A test that permits the identification of specific cell types within a sample of cells. The
test may be used to examine blood cells, marrow cells or cells from a biopsy.
A diluted
suspension of cells from one of these sources can be tagged with an antibody specific
for a site on the cell surface. The antibody has a chemical attached that will emit light
when activated by a laser beam.
The cells flow through the instrument called a “flow
cytometer”; when the cells pass through its laser beam, those with the antibody-
specific surface feature light up and then can be counted. One use of flow cytometry is
to determine whether a sample of cells is composed of T cells or B cells. This permits
the physician to determine if the leukaemia or lymphoma is of the B- or T-cell type.
Flow cytometry is also used to select stem cells from a mixed-cell population so that
they can be used later in a stem cell transplant.
FLT3
An abbreviation for the Fms-like tyrosine kinase 3 gene (Often pronounced as flit 3).
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.
Fluorescent in Situ Hybridization (FISH)
This is a technique in which DNA probes tagged with fluorescent molecules that emit light of different wavelengths (and different colours) are used on tissue. The probes match to the chromosomes within the cells, and the chromosomes fluoresce in colour. FISH is a means of studying chromosomes in tissue.
Fungus
A microbe often referred to as a “mould” or “yeast.” There are many species of fungi, and some, while relatively harmless in people with healthy immune systems, are prone to produce serious infections in people who are immunosuppressed, as after stem cell transplantation or multiple treatments with high-dose chemotherapy for progressive leukaemia or lymphoma. Fungi belong to the genera Candida, Aspergillus and Histoplasma, among others.
G-CSF (Granulocyte Colony-Stimulating Factor)
See Growth Factor.
GM-CSF (Granulocyte-Macrophage Colony-Stimulating Factor)
See Growth Factor
Graft-Versus-Host Disease (GVHD)
This is the immune attack by lymphocytes in a donor’s marrow or blood cell suspension (the graft) against the tissues of the recipient (the host).
The immune cells most engaged in this reaction are donor T lymphocytes, which are present in the donor’s blood or marrow, the source of the stem cells. The principal sites of injury are the skin, the liver and the gastrointestinal tract. The reaction does not occur in identical twin transplants.
The reaction may be minimal in closely matched individuals or severe in less well-matched individuals. These reactions are mediated in part by antigens that are not in the major HLAsystem and cannot be matched prior to transplantation.
For example, in the case of a female stem cell donor and a male recipient, factors that are produced by genes on the male recipient’s Y chromosome may be seen as foreign by the female donor’s cells, which do not share the genes on the Y chromosome. This fact does not prohibit female donors and male recipients, but it makes the risk of immune reaction higher.
Graft-Versus-Tumour Effect (Graft-Versus-Leukaemia Effect)
This is the potential immune reaction of transplanted (donor) T lymphocytes to recognize and attack the malignant cells of the recipient. This effect was noted when 1) disease recurrence after transplant was seen to be more likely if the donor and recipient were identical twins than if they were non-identical siblings; 2) disease recurrence was less likely the more pronounced the graft-versus-host disease (GVHD) was; and 3) the removal of donor T lymphocytes decreased the incidence of GVHD but also resulted in a higher frequency of disease relapse. Each of these observations could be explained best as an immune attack by donor lymphocytes against recipient tumour cells that, along with the intensive conditioning treatment, serves to keep the disease in check.
This effect seems to be most active in types of myeloid leukaemia, although it may also occur in patients with other blood cancers.
Granulocyte
A type of white cell that has a large number of granules in the cell body. Neutrophils, eosinophils and basophils are types of granulocytes.
Granulocytic Sarcoma
See Chloroma
Growth Factor
A chemical used to stimulate the production of neutrophils and shorten the period of low neutrophil counts in the blood after chemotherapy. Granulocyte colony-stimulating factor (G-CSF) and granulocyte-macrophage colony-stimulating factor (GM-CSF) are examples of growth factors that are made commercially. GM-CSF can also stimulate monocytes.
Haematocrit
The proportion of the blood occupied by the red cells. Normal values are 40 to 54 per cent in males and 35 to 47 per cent in females. If the haematocrit is below normal, the condition is called “anaemia.” If the haematocrit is above normal, the condition is called “erythrocytosis.”
Haematologist
A medical doctor who specialises in the treatment of blood cell diseases..
Haematopathologist
A type of pathologist who studies diseases of blood cells by looking at peripheral blood smears, bone marrow aspirates and biopsies, and lymph nodes and other tissues. The haematopathologist uses his or her expertise to identify diseases such as blood cancers. In addition to using a microscope, a haematopathologist also uses laboratory values, flow cytometry and molecular diagnostic tests to make the most accurate diagnosis. The haematopathologist works closely with the haematologist/oncologist who sees the patient and decides on the best treatment based upon the diagnosis.
Haematopoiesis
The process of blood cell development in the marrow. The most undeveloped cells in the marrow are stem cells. They start the process of blood cell development. The stem cells begin to develop into young or immature blood cells such as red cells or white cells of various types. This process is called “differentiation.”
The young or immature blood cells then further develop into fully functional blood cells. This process is called “maturation.” The mature cells leave the marrow, enter the blood and circulate throughout the body. Haematopoiesis is a continuous process that is active normally throughout life. The reason for this activity is that most blood cells live for short periods and must be continually replaced. Red cells live for months, platelets live for a week or two, and white cells live for a few days. About 500 billion blood cells are made each day. When the marrow is invaded with cancer cells, it cannot produce enough normal blood cells to meet the constant demand for them, and the numbers in the blood cell counts become severely depleted.
Haemoglobin
The iron-containing pigment in red cells that carries oxygen to the tissue cells. A reduction in the number of red cells decreases the amount of haemoglobin in the blood. A decreased blood haemoglobin concentration is called “anaemia.” A low haemoglobin concentration decreases the oxygen-carrying capacity of blood. If severe, this decreased capacity may limit a person’s ability to exert him or herself. Normal values of blood haemoglobin are 12 to 16 grams per decilitre (g/dL). Compared to men, healthy women have, on average, about 10 per cent less haemoglobin in their blood.
HLA
The abbreviation for human leukocyte antigen(s). These are proteins on the surface of most tissue cells, and they give an individual his or her unique tissue type. HLA factors are inherited from mother and father, and the greatest chance of having the same HLA type is between siblings. On average, one in four siblings is expected to share the same HLA type. The testing for HLA factors is referred to as “tissue typing.” There are six major groups of HLA: A, B, C, D, Dr, and Dq. These proteins on the surface of cells act as antigens when donated (transplanted) to another individual, the recipient. If the antigens on the donor cells are identical (as in identical twins) or very similar (as in HLA-matched siblings), the transplant Acute Myeloid Leukaemia (donated stem cells) is more likely to survive (engraft) in the recipient. In addition, the recipient’s body cells are less likely to be attacked by the donated immune cells (a result called “graft-versus-host disease”).
Immune System
Made up from cells and proteins that defend the body against infection. Lymphocytes, lymph nodes and the spleen are parts of the body’s immune system.
Immunity
The ability to resist infection
Immunophenotyping
A method that uses the reaction of antibodies with cell antigens to determine a specific type of cell in a sample of blood cells, marrow cells or lymph node cells. The antibodies react with specific antigens on the cell. A tag is attached to an antibody so that it can be detected.
The tag can be identified by the laboratory detector used for the test. As cells carrying their array of antigens are tagged with specific antibodies, they can be identified; for example, myeloid leukaemic cells can be distinguished from lymphocytic leukaemic cells. Normal lymphocytes may be distinguished from leukaemic lymphocytes. This method also helps sub-classify cell types, information that may, in turn, help in deciding on the best treatment to apply in that type of leukaemia or lymphoma. The antigen on a cell is referred to as a “cluster designation” or “CD,” with an associated number. For example, CD10, also referred to as “CALLA” (common acute lymphoblastic leukaemia antigen), may be present on leukaemic lymphoblasts and CD33, and may be present on leukaemic myeloblasts.
Immunosuppression
Refers to 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. This can occur as a result of intensive chemotherapy and radiation therapy, especially when used in high doses to condition a patient for transplantation. It can also occur because of disease states. Human immunodeficiency virus (HIV) infection is one such disease. Graft-versus-host disease (GVHD) creates an immunosuppressive state in which immune protection against infection is inadequate. In the transplant patient the conditioning regimen and severe GVHD can result in overwhelming infection. See Graft-Versus-Host Disease.
Immunotoxins
See Monoclonal Antibody Therapy
Indwelling Catheter
See Central Line
Intrathecal
This is the designation for the space between the covering or lining of the central nervous system (CNS) and the brain or spinal cord. This lining is called the “meninges.” In some situations, drugs have to be administered directly into the spinal canal when leukaemia cells are in the meninges. This is called “Intrathecal therapy.”
Inversion
An abnormality of chromosomes that occurs when a section of a chromosome breaks and turns upside down, so that its genetic material is in reverse order but the inverted piece remains attached to the chromosome.
Karyotype
The systematic arrangement, using images, of the 46 chromosomes in the human cell in 22 matched pairs (maternal and paternal member of each pair) by length from longest to shortest and other features, with the sex chromosomes shown as a separate pair (either XX or XY). The 22 pairs are referred to as “autosomes.”
Leukocytes
See White Cells
Leukocytosis
An increase above the upper limit of normal in the concentration of blood leukocytes (white cells).
Leukopenia
A decrease below normal in the concentration of blood leukocytes (white cells).
Lumbar Puncture
A procedure to remove spinal fluid from the space surrounding the spinal cord or to administer anticancer drugs to prevent or treat leukaemia or lymphoma of the coverings of the central nervous system (CNS). The doctor first injects a local anaesthetic, then inserts a needle between two vertebrae in the lower part of the back. Fluid samples are collected in sterile tubes and examined for evidence of leukaemia or lymphoma. A lumbar puncture is not often used to test forAML, but may be used if the patient is having symptoms that could be caused by the spread of leukaemia cells into the CNS. Another term for lumbar puncture is “spinal tap.”
Lymph Nodes
Small structures (the size of beans) that contain large numbers of lymphocytes and are connected with each other by small system of channels called the lymphatic system. These nodes are distributed throughout the body. Enlarged lymph nodes can be seen, felt or measured by computed tomography (CT) scan or magnetic resonance imaging (MRI) depending on their location and the degree of enlargement.
Lymphocyte
A type of white cell that is the essential cell type in the body’s immune system. There are three major types of lymphocytes: B lymphocytes, which produce antibodies to help combat infectious agents like bacteria, viruses and fungi; T lymphocytes, which have several functions, including assisting B lymphocytes to make antibodies; and natural killer (NK) cells, which can attack virus-infected cells or tumour cells.
Macrophage
See Monocyte
Marrow
See Bone Marrow
Micro litre (µL) of Blood
A measurement used for some blood test results. One micro litre (μL) is an amount equal to one one-millionth of a litre, which is almost equal to a quart of blood.
Mini-transplant
See Reduced-Intensity Stem Cell Transplantation
Minimal Residual Disease (MRD)
The small amounts of cancer cells that may remain after treatment, even when blood and marrow may appear to be normal. These residual cells can only be identified by sensitive molecular techniques.
Monoclonal
See Clonal
Monoclonal Antibodies
Antibodies made by cells belonging to a single clone. These highly specific antibodies can be produced in the laboratory. They are very important reagents for identifying and classifying disease by the immunophenotyping of cells. They also have clinical applications for targeted delivery of drugs to cancer cells and can be used to purify cells used for stem cell transplants.
Monoclonal Antibody Therapy
Therapy using proteins made in the laboratory that either react with or attach to antigens on the cancer cells to which they are targeted. The antibodies are used therapeutically in three ways: as “naked” antibodies (monoclonal antibodies); as antibodies to which radioactive isotopes are attached (radio-immunotherapies); and as antibodies to which toxins are attached (Immunotoxins).
Monocyte/Macrophage
A type of white cell that represents about 5 to 10 per cent of the cells in normal human blood. The monocyte and the neutrophil are the two major microbe-eating and microbe-killing cells in the blood.
When monocytes leave the blood and enter the tissue, they are converted to macrophages. The macrophage is the monocyte-in-action: it can combat infection in the tissues, ingest dead cells (in this function it is called a “scavenger cell”) and assist lymphocytes in their immune functions.
Multidrug Resistance (MDR)
A characteristic of cells that makes them resistant to the effects of several different classes of drugs. There are several forms of drug resistance.
One type of MDR involves the ability to force several drugs out of the cell. The outer wall, or membrane, of the cell contains a pump that ejects chemicals, preventing them from reaching a toxic concentration.
The resistance to drugs can be traced to the expression of genes that direct the formation of high amounts of a protein that prevents the drugs from affecting the malignant cells. If the gene or genes involved are not expressed or are weakly expressed, the cells are more sensitive to the drug’s effect. If the genes are highly expressed, the cells are less sensitive to the drug’s effect.
Mutation
An alteration in a gene that results from a change to the part of the DNA that represents that gene. A “germ cell mutation” is present in the egg or the sperm and can be transmitted from parent(s) to offspring. A “somatic cell mutation” occurs in a specific tissue cell and can result in the growth of that tissue cell into a tumour. Most cancers start after a somatic mutation. In leukaemia, lymphoma or myeloma, a primitive marrow (blood-forming) or lymph node cell undergoes one or more somatic mutations, leading to the formation of a tumour. If the mutation results from a major abnormality of chromosomes, such as a translocation, it can be detected by cytogenetic examination. Sometimes the alteration in the gene is subtler and requires more sensitive tests to identify the oncogene.
Myeloblasts
See Blast Cells
Myelocyte
A cell of the marrow that is a precursor of the mature granulocytes of the blood. Myelocytes are not present in the blood of healthy individuals.
Neutropenia
A decrease below normal levels in the concentration of neutrophils in the blood, (neutrophil – a type of white cell.)
Neutrophil
The principal phagocyte (microbe-eating cell) in the blood; this blood cell is the main cell that combats infections. Often, it is not present in sufficient quantities in patients with acute leukaemia or after chemotherapy. A severe deficiency of neutrophils increases the patient’s susceptibility to infection. A neutrophil may be called a “poly” (polymorphonuclear neutrophil) or “seg” (segmented neutrophil) because its nucleus has several lobes.
Non-myeloablative transplant
See Reduced-Intensity Stem Cell Transplantation
Oncogene
A mutated gene that is the cause of a cancer. Several subtypes of acute myeloid leukaemia, acute lymphocytic leukaemia and lymphoma, and nearly all cases of chronic myeloid leukaemia are associated with an oncogene.
Oncologist
A medical doctor who diagnoses and treats patients with cancer. Oncologists are usually hospital consultants who treat adults or paediatricians who treat children.
Clinical oncologists specialize in the use of radiation as well as medication to treat cancer; medical oncologists use only medication to treat cancer, and defer to clinical oncologist for radio therapy; and surgical oncologists specialize in the use of surgical procedures to diagnose and treat cancer.
These doctors cooperate and collaborate to provide the best treatment plan (surgery, radiation therapy, chemotherapy or immunotherapy) for the patient.
Pancytopenia
A decrease below normal in the concentration of the three major blood cell types: red cells, white cells and platelets.
Pathologist
A medical doctor who identifies disease by studying tissues under a microscope. See Haematopathologist.
Peripheral Blood Smear
A sample of blood placed on a slide and dyed so that the cells can be examined under a microscope.
Peripherally Inserted Central Catheter (PICC or PIC Line)
A long, thin, flexible tube that is inserted into the body and used to administer medications, antibiotics, fluids and nutrition for an extended period of time. It can also be used to obtain blood samples. Prior to insertion of the PICC, the patient is given a local anaesthetic to numb the arm between the elbow and the shoulder. The PICC is inserted through the skin into a vein in the arm and advanced until it reaches the superior vena cava just above the heart. The superior vena cava is one of the veins in the central venous system. The PICC can be maintained for several weeks to months, eliminating the need for standard intravenous (IV) administration.
Petechiae
Pinhead-sized sites of bleeding in the skin. This type of bleeding results from a very low platelet count. The small punctate (spotted; marked with points or punctures) haemorrhages are frequently seen on the legs, feet, trunk and arms. They evolve from red to brown and eventually disappear. They stop developing when the platelet count increases.
Phagocytes
Cells that readily eat (ingest) microorganisms such as bacteria and fungi and kill them as a means of protecting the body against infection. The two principal phagocytes are neutrophils and monocytes. They leave the blood and enter tissues in which an infection has developed. A severe decrease in the concentration of these cells is the principal cause of susceptibility to infection in patients treated with intensive radiation therapy and/or chemotherapy. Treatment may suppress blood cell production in the marrow, resulting in deficiencies of these phagocytic cells.
PIC/PICC Line
See Peripherally Inserted Central Catheter
Plasma
The liquid portion of the blood, in which the blood cells, platelets, proteins and various other components are suspended. It is also referred to as “blood plasma.”
Platelet Transfusion
Transfusion of donor platelets, which may be needed to support some patients treated for blood cancer. The platelets can be gathered from several unrelated donors and given as pooled, random-donor platelets. The platelets from about six single-unit blood donors are required to significantly raise the platelet count in a recipient. Sufficient platelets can be obtained from one donor by a procedure known as “apheresis.” This technique skims the platelets from large volumes of blood as it passes through the apheresis machine. The red cells and plasma are returned to the donor. The advantage of single-donor platelets is that the patient is not exposed to the different antigens on platelets from many different people and thus is less likely to develop antibodies against donor platelets. HLA-matched platelet transfusion can be given from a related donor who has an identical or very similar HLA tissue type.
Platelets
Small blood cells (about one-tenth the volume of red cells) that stick to the site of blood vessel injury aggregate and then seal off the injured blood vessel to stop bleeding. “Thrombocyte” is another name for platelet and is often used as the prefix in terms describing disorders of platelets, such as thrombocytopenia (too few) or thrombocythemia (too many).
Polymerase Chain Reaction (PCR)
A technique to expand trace amounts of DNA or RNA so that the specific type of the DNA or RNAcan be determined or studied. This technique has become useful in detecting a very low concentration of residual blood cancer cells, too few to be seen using a microscope. PCR can detect the presence of one blood cancer cell among 500,000 to 1 million blood cells. PCR requires a specific DNA (or RNA) abnormality or marker, like an oncogene, in the leukaemia or lymphoma cells in order to be used for identifying residual abnormal cells.
Port
A port is a small device that is used with a central line to access a vein. The port is placed under the skin of the chest. To take blood samples (or to give medicines or nutrition) the doctor or nurse puts a needle through the skin into the port. A numbing cream can be put on the skin before the port is used.
Promyelocyte
A cell of the marrow that is very early in development along the pathway to myeloid cells. It represents the next stage after the blast cell stage.
Radiation Therapy
The use of x-rays and other forms of radiation in treatment. Radiation therapy may be useful in the treatment of some localized blood cancers. Radiation therapy can be an important adjunct to therapy when there are particularly large masses in a localized area or when local large lymph nodes are compressing or invading normal organs or structures and chemotherapy cannot control the problem.
Radioimmunotherapy
See Monoclonal Antibody Therapy.
Recurrence/Relapse
The return of a disease after it has been in remission following treatment.
Red Cells
Blood cells (erythrocytes) that carry haemoglobin, which binds oxygen and carries it to the tissues of the body. The red cells make up about 40 to 45 per cent of the volume of the blood in healthy individuals.
Reduced-Intensity Stem Cell Transplantation
(sometimes called a mini-transplant also called a non-myeloablative transplant) is a type of allogeneic transplant. In a reduced-intensity transplant, patients receive lower doses of chemotherapy drugs and/or radiation in preparation for the transplant.
Immunosuppressive drugs are used to prevent rejection of the graft (donor tissue), and the engraftment of donor immune cells may allow these cells to attack the disease (graft-versus-leukaemia effect). More study is needed to determine the effectiveness of this treatment for non-Hodgkin lymphoma patients. Studies to determine the usefulness of reduced-intensity stem cell transplantation in older patients are also under way.
Refractory Disease
This is disease that does not go into remission or improve substantially after treatment with standard therapy for the disease. Newly diagnosed patients or relapsed patients may have refractory disease. See Resistance to Treatment.
Relapsed Disease
Disease that initially responded to therapy but has begun to progress.
Remission
The disappearance of evidence of a disease, usually as a result of treatment is called remission. The terms “complete” and “partial” are sometimes used to modify the term a “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. Long-term benefit usually requires a complete remission, especially in acute leukaemia or progressive lymphomas.
Resistance to Treatment
The ability of cells to live and divide despite their exposure to a chemical that ordinarily kills cells or inhibits their growth. Refractory leukaemia is the condition in which a proportion of malignant cells resists the damaging effects of a drug or drugs. Cells have several ways to develop drug resistance. See Multidrug Resistance.
Risk Factor
A factor that is scientifically established to increase a person’s chance of getting a disease is referred to as a risk factor. Risk factors can be classified as either genetic (inherited), lifestyle related, or environmental. The presence of one or more risk factors does not mean that a person will necessarily develop the disease. In the case of environmental exposure, the extent of exposure and its duration are important considerations in determining if risk is increased.
RNA
The abbreviation for ribonucleic acid, a molecule in cells that carries out DNA’s instructions for making proteins.
Sedimentation Rate
This is a blood test that measures how quickly red cells (erythrocytes) settle in a test tube in 1 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 “sed rate” or “erythrocyte sedimentation rate (ESR).”
Serum
This is the liquid portion of the blood in which no cells are present.
Somatic Cell Mutation
See Mutation
Spinal Tap
See Lumbar Puncture
Spleen
An organ located in the left upper portion of the abdomen just under the left side of the diaphragm. It contains clusters of lymphocytes and also filters old or worn-out cells from the blood. It is often affected in lymphocytic leukaemia and lymphoma.
Enlargement of the spleen is called “splenomegaly.” Surgical removal of the spleen is known as “splenectomy.” Certain diseases are treated by removing the spleen. Most of the functions of the spleen can be performed by other organs, such as the lymph nodes and liver, but a person whose spleen has been removed is at higher risk for infection. He or she is given antibiotic therapy immediately at the first sign of infection, such as a fever.
Stem Cell Transplantation
See Allogeneic Stem Cell Transplantation; Autologous Stem Cell Transplantation.
Stem Cells
Are primitive cells in marrow that develop into red cells, white cells and platelets. Stem cells are largely found in the marrow, but some leave the marrow and circulate in the blood. Using special techniques, the stem cells in the blood can be collected, preserved by freezing and later thawed and used for stem cell therapy. See Haematopoiesis.
Thrombocythemia
An above-normal concentration of platelets in the blood.
Thrombocytopenia
A below-normal concentration of platelets in the blood.
Toxin
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.
Translocation
An abnormality of chromosomes in 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 occurs, 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.
Transplantation
See Allogeneic Stem Cell Transplantation; Autologous Stem Cell Transplantation.
Tumour Suppressor Gene
This is a gene that acts to prevent cell growth. If a mutation occurs in this gene that “turns off” the gene and causes loss of function, it may make the individual more susceptible to the development of cancer in the tissue in which the mutation occurred. Another term for tumour suppressor gene is “anti-oncogene.”
White Cells
Any of the five major types of infection-fighting cells in the blood: neutrophils, eosinophils, basophils, monocytes and lymphocytes. White cells are also called “leukocytes.”