{a}

acute leukemia: A rapidly progressing cancer of the blood-forming tissue (bone marrow).

anemia: A condition in which the number of red blood cells is below normal.

antibiotic: A drug used to treat infections caused by bacteria and other microorganisms.

{b}

biological therapy: Treatment to stimulate or restore the ability of the immune system to fight infection and disease. Also used to lessen side effects that may be caused by some cancer treatments. Also known as immunotherapy, biotherapy, or biological response modifier (BRM) therapy.

blasts: Immature blood cells.

blood-brain barrier: A network of blood vessels with closely spaced cells that makes it difficult for potentially toxic substances (such as anticancer drugs) to penetrate the blood vessel walls and enter the brain.

bone marrow: The soft, sponge-like tissue in the center of bones that produces white blood cells, red blood cells, and platelets.

bone marrow aspiration: The removal of a small sample of bone marrow (usually from the hip) through a needle for examination under a microscope.

bone marrow biopsy: The removal of a sample of tissue from the bone marrow with a needle for examination under a microscope.

bone marrow transplantation: A procedure to replace bone marrow destroyed by treatment with high doses of anticancer drugs or radiation. Transplantation may be autologous (an individual's own marrow saved before treatment), allogeneic (marrow donated by someone else), or syngeneic (marrow donated by an identical twin).

{c}

cancer: A term for diseases in which abnormal cells divide without control. Cancer cells can invade nearby tissues and can spread through the bloodstream and lymphatic system to other parts of the body.

catheter: A flexible tube used to deliver fluids into or withdraw fluids from the body.

central nervous system: The brain and spinal cord.

cerebrospinal fluid: The fluid flowing around the brain and spinal cord. Cerebrospinal fluid is produced in the ventricles in the brain.

chemotherapy: Treatment with anticancer drugs.

chronic leukemia: A slowly progressing cancer of the blood-forming tissues.

clinical trial: A research study that tests how well new medical treatments or other interventions work in people. Each study is designed to test new methods of screening, prevention, diagnosis, or treatment of a disease.

colony-stimulating factors: Substances that stimulate the production of blood cells. Colony-stimulating factors include granulocyte colony-stimulating factors (also called G-CSF and filgrastim), granulocyte-macrophage colony-stimulating factors (also called GM-CSF and sargramostim), and promegapoietin.

{d}

digestive tract: The organs through which food passes when food is eaten. These organs are the mouth, esophagus, stomach, small and large intestines, and rectum.

{e}

erythrocytes: Cells that carry oxygen to all parts of the body. Also called red blood cells (RBCs).

{f}

fertility: The ability to produce children.

{g}

genetic: Inherited; having to do with information that is passed from parents to offspring through genes in sperm and egg cells.

graft-versus-host disease: GVHD. A reaction of donated bone marrow or peripheral stem cells against a person's tissue.

{h}

hairy cell leukemia: A type of chronic leukemia in which the abnormal white blood cells appear to be covered with tiny hairs when viewed under a microscope.

hematologist: A doctor who specializes in treating diseases of the blood.

{i}

immune system: The complex group of organs and cells that defends the body against infection or disease.

interferon: A biological response modifier (a substance that can improve the body's natural response to disease). Interferons interfere with the division of cancer cells and can slow tumor growth. There are several types of interferons, including interferon-alpha, -beta, and -gamma. These substances are normally produced by the body. They are also made in the laboratory for use in treating cancer and other diseases.

interleukins: Biological response modifiers (substances that can improve the body's natural response to disease) that help the immune system fight infection and cancer. These substances are normally produced by the body. They are also made in the laboratory for use in treating cancer and other diseases.

intrathecal chemotherapy: Anticancer drugs that are injected into the fluid-filled space between the thin layers of tissue that cover the brain and spinal cord.

intravenous: IV. Into a vein.

{k}

kidneys: A pair of organs in the abdomen that remove waste from the blood (as urine), produce erythropoietin, and are responsible for the long-term regulation of blood pressure.

{l}

leukemia: Cancer of blood-forming tissue.

leukocytes: Cells that help the body fight infections and other diseases. Also called white blood cells (WBCs).

liver: A large, glandular organ located in the upper abdomen. The liver cleanses the blood and aids in digestion by secreting bile.

lumbar puncture: A procedure in which a needle is put into the lower part of the spinal column to collect cerebrospinal fluid or to give anticancer drugs intrathecally. Also called a spinal tap.

lymph node: A rounded mass of lymphatic tissue that is surrounded by a capsule of connective tissue. Also known as a lymph gland. Lymph nodes are spread out along lymphatic vessels and contain many lymphocytes, which filter the lymphatic fluid (lymph).

lymphocytic: Referring to lymphocytes, a type of white blood cell.

lymphoid: Referring to lymphocytes, a type of white blood cell. Also refers to tissue in which lymphocytes develop.

{m}

monoclonal antibodies: Laboratory-produced substances that can locate and bind to cancer cells wherever they are in the body. Many monoclonal antibodies are used in cancer detection or therapy; each one recognizes a different protein on certain cancer cells. Monoclonal antibodies can be used alone, or they can be used to deliver drugs, toxins, or radioactive material directly to a tumor.

myelogenous: Produced by, or originating in, the bone marrow.

myeloid: Pertaining to, derived from, or manifesting certain features of the bone marrow. In some cases also pertains to certain types of non-lymphocyte white blood cells found in the bone marrow, including granulocyte, monocyte, and platelet lineages. Also called myelogenous.

{o}

ommaya reservoir: A device surgically placed under the scalp and used to deliver anticancer drugs to the fluid surrounding the brain and spinal cord.

oncologist: A doctor who specializes in treating cancer. Some oncologists specialize in a particular type of cancer treatment. For example, a radiation oncologist specializes in treating cancer with radiation.

{p}

pathologist: A doctor who identifies diseases by studying cells and tissues under a microscope.

pediatric: Having to do with children.

petechiae: Pinpoint, unraised, round red spots under the skin caused by bleeding.

plasma: The clear, yellowish, fluid part of the blood that carries the blood cells. The proteins that form blood clots are in plasma.

platelets: A type of blood cell that helps prevent bleeding by causing blood clots to form. Also called thrombocytes.

prognosis: The likely outcome or course of a disease; the chance of recovery or recurrence.

{r}

radiation therapy: The use of high-energy radiation from x-rays, neutrons, and other sources to kill cancer cells and shrink tumors. Radiation may come from a machine outside the body (external-beam radiation therapy) or from material called radioisotopes. Radioisotopes produce radiation and can be placed in or near a tumor or near cancer cells. This type of radiation treatment is called internal radiation therapy, implant radiation, or brachytherapy. Systemic radiation therapy uses a radioactive substance such as a radiolabeled monoclonal antibody that circulates throughout the body. Also called radiotherapy.

recur: To occur again. Recurrence is the return of cancer, at the same site as the original (primary) tumor or in another location, after the tumor had disappeared.

red blood cells: RBCs. Cells that carry oxygen to all parts of the body. Also called erythrocytes.

relapse: The return of signs and symptoms of cancer after a period of improvement.

remission: A decrease in or disappearance of signs and symptoms of cancer. In partial remission, some, but not all, signs and symptoms of cancer have disappeared. In complete remission, all signs and symptoms of cancer have disappeared, although there still may be cancer in the body.

risk factor: A habit, trait, condition, or genetic alteration that increases a person's chance of developing a disease.

{s}

seizures: Convulsions; sudden, involuntary movements of the muscles.

spleen: An organ that is part of the lymphatic system. The spleen produces lymphocytes, filters the blood, stores blood cells, and destroys old blood cells. It is located on the left side of the abdomen near the stomach.

splenectomy: An operation to remove the spleen.

supportive care: Treatment given to prevent, control, or relieve complications and side effects and to improve the comfort and quality of life of people who have cancer.

{t}

testicles: The two egg-shaped glands found inside the scrotum. They produce sperm and male hormones. Also called testes.

thrombocytes: Blood cells that help prevent bleeding by causing blood clots to form. Also called platelets.

transfusion: The infusion of components of blood or whole blood into the bloodstream. The blood may be donated from another person, or it may have been taken from the person earlier and stored until needed.

{w}

white blood cell: A type of cell in the immune system that helps the body fight infection and disease. White blood cells include lymphocytes, granulocytes, macrophages, and others.

{x}

x-ray: High-energy radiation used in low doses to diagnose diseases and in high doses to treat cancer.