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Campath: Campath is indicated for the treatment of B-cell Chronic Lymphocytic Leukemia (B-CLL) in patients who have been treated with alkylating agents and who have failed fludarabine therapy.

Cancer: A disease that results from a mutation in a single cell in a tissue. The change in DNA results in the uncontrolled growth and/or persistence of cells. Neoplasm is a synonym for cancer. Malignancy is another synonym for cancer, but it also implies a progressive cancer in contrast with a benign cancer.

Carcinogen: A substance that has the ability to cause cells to become cancerous if the exposure is above a certain dose and duration. There are very few established chemical leukemogens or lymphomagens. Chronic exposure to benzene has been established to cause acute myelogenous leukemia. Certain chemotherapeutic agents administered to patients with other types of cancer can increase the risk of developing acute myelogenous leukemia. Agents such as organic herbicides or pesticides are under investigation as possible lymphomagens.

Carcinogenesis: The process by which cancer develops.

Cell Markers: see Immunophenotype

Central Nervous System (CNS): The brain and the spinal cord. This term distinguishes these portions of the nervous system from the vast network of peripheral nerves that emerge from the brain and spinal cord.

Central Venous Line: A catheter passed through a blood vessel into a large vein; these are used for patients undergoing intensive, prolonged chemotherapy. The central catheter permits taking blood samples and administering drugs, blood products, and nutrition without repeated needle puncture of a vein.

Chemotherapy: The use of chemicals (drugs or medications) to kill malignant T-cells. Numerous chemicals have been developed for this purpose, and most act to injure the DNA of the cells. When the DNA is injured, the cells cannot grow or survive. Successful chemotherapy depends on the fact that malignant T-cells are somewhat more sensitive to the chemicals than normal cells. Because the cells of the marrow, the intestinal tract, the skin, and hair follicles are most sensitive to these chemicals, injury to these organs cause the common side effects of chemotherapy, i.e. mouth sores and hair loss.

Chromosome: The nucleus of all human cells contains 46 structures called chromosomes. The genes, specific stretches of DNA, are the principal structures that make up the chromosomes. An “average” sized chromosome contains enough DNA to account for about 2000 genes. This accounts for the estimate that the human genome has about 90,000 genes (46 x 2000). The genes on the X and Y chromosomes, the sex chromosomes, are the determinants of our gender: two X-chromosomes in females and an X and an Y chromosome in males. The number or shape of chromosomes may be altered in lymphoma or leukemia cells.

Chronic Leukemia: A malignant disease of the bone marrow and blood that progresses slowly and permits greater numbers of more mature, functional cells to be made. There are two major types of chronic leukemia: Chronic Myelogenous Leukemia (CML) and Chronic Lymphocytic Leukemia (CLL). Each has several subtypes. CLL is a common type of leukemia in older adults, accounting for approximately 7,500 new cases each year. CML strikes about 4,500 persons each year.

Chronic Lymphocytic Leukemia (CLL): A slowly progressive form of lymphocytic leukemia, characterized by an increased number of the B-lymphocytes in the marrow and blood. Enlargement of lymph nodes and the spleen occur commonly. It is the most prevalent form of leukemia and occurs predominantly after age 55 years. It may be diagnosed by chance before the patient develops any clinical symptoms of disease.

Clinical Trial: A carefully planned study of a new drug or treatment approach or a new application of an existing drug or approach. In a Phase I trial, a new agent that has been tested on cells and then animals in the laboratory, is examined in a relatively small number of volunteers, often with advanced disease and poorly responsive or unresponsive to existing treatment. This is to assess dosages, patient tolerance, and acute toxic effects. If efficacy is evident, the new approach may be tested in a Phase II trial in which more patients are studied and more information gathered on dosage, effects, and toxicity. In a phase III trial, the drug or drugs or new approaches are compared in patients who are randomized to receive the current existing best treatment or the new treatment. Larger numbers of patients are studied. An effort is made to minimize observer bias. Careful analysis of results is performed. Such trials are required to gain the information required by the Food and Drug Administration to determine efficacy and safety before approving a drug for marketing. Federal guidelines for informed consent of participants must be followed.

Clotting Factors: Chemical constituents of the blood, which in response to blood vessel injury, interact in sequence to result in a clot.

Congenital Leukemia: The presence of leukemia at the time of birth.

Corticosteriods: see Glucocorticoids

Cryoglobulins: These are proteins, called immunoglobulins, which congeal or gel at cold temperatures. These proteins are made by B-lymphocytes or their derivative cells, plasma cells. They may congeal in the blood in vessels exposed to lower temperatures, such in the skin blood vessels, especially in winter months. Pain, discoloration and other changes in the skin can result. Cryoglobulins may be made by myeloma cells or B-cell lymphomas.

Cryopreservation: A technique used to keep frozen cells intact and functional for many years. Blood or marrow cells, including stem cells, can be stored for very long periods and remain functional if they are suspended in a fluid that contains a chemical that prevents cellular injury during freezing or thawing. This chemical is referred to as a cryoprotective agent. Glycerol is one of the most commonly used of such chemicals. The freezing temperature required to preserve cells is much lower (colder) than that of a household freezer. Stem cells used for later autologous transplantation are cryopreserved.

Cultures: If an infection is suspected, it is helpful to know the principal site and the type of bacterium, fungus or other microorganism involved so that the most specific antibiotics can be selected for treatment. To determine the site and organism, samples of body fluids such as sputum, blood and urine, swabs of the inside of the nose, throat, and rectum, and stool samples are placed on culture medium in special sterile containers and incubated at body temperature (37º C, 98.6º F) for one to several days. These cultures are examined to determine if bacteria or fungi are present in significant numbers. If they are present, the organisms can be identified and tested with several antibiotics to determine which antibiotic kills the organism. This process determines the “antibiotic sensitivity” of the organism.

Cycle of Treatment: The term designates an intensive, clustered period of chemotherapy (and/or radiotherapy). The treatment may be given for several days or weeks and represents one cycle of treatment. The treatment plan may call for two, three, or more cycles of treatment.

Cytogenetics: The process of analyzing the number and shape of the chromosomes of cells. The individual, who prepares, examines, and interprets the number and shape of chromosomes in cells is called a cytogeneticist. In addition to identifying chromosome alterations, the specific genes affected can be identified in some cases. These findings are very helpful in diagnosing specific types of leukemia and lymphoma, in determining treatment approaches, and in following the response to treatment.

Cytokines: These are cell-derived chemicals that are secreted by various types of cells and act on other cells to stimulate or inhibit their function. Chemicals derived from lymphocytes are called “lymphokines.” Chemicals derived from lymphocytes that act on other white blood cells are called “interleukins,” that is, they interact between two types of leukocytes. Some cytokines can be made commercially and used in treatment. Granulocyte-colony-stimulating factor (G-CSF) is one such cytokine. It stimulates the production of neutrophils and shortens the period of low neutrophil counts in the blood after chemotherapy. Cytokines that stimulate cell growth are sometimes referred to as “growth factors.”

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

Cytotoxic Drugs: Anti-cancer drugs that act by killing or preventing the division of cells. (See chemotherapy.)