Accelerated phase: Chronic myelogenous leukemia that is progressing is said to be in accelerated phase. The number of immature, abnormal white blood cells in the bone marrow and blood is higher than in the chronic phase, but not as high as in the blast phase. The merging of the "stable phase" of the disease into the accelerated phase can be as subtle as the need for increasing doses of chemotherapy or as obvious as pain in the bones, joints or spleen, sweating, fatigue and unexplained fevers.

Acetaminophen: A drug that reduces pain and fever (but not inflammation).

Acute: When symptoms or a disease happens suddenly.

Acute Lymphocytic Leukemia (ALL): Cancer of the blood cells. A disease in which too many immature white blood cells that give rise to lymphocytes are found in the blood and bone marrow. The immature white blood cells are referred to as lymphoblasts. The disease often results in the replacement of normal bone marrow with lymphoblasts that crowd out normal cells. The progression of this disease is usually rapid. ALL appears most commonly in children although it can appear in adults.

Acute Myelogenous or Non-lymphocytic Leukemia (AML): Cancer of the blood cells. Normally, the bone marrow makes cells called blasts that develop (mature) into several different types of blood cells that have specific jobs to do in the body. AML affects the blasts that develop into white blood cells called granulocytes or neutrophils. In AML, the blasts do not mature and become too numerous and crowd out normal cells. The progression of this disease is usually rapid. AML occurs in all ages and is the more common acute leukemia in adults. Also called acute myeloid leukemia or acute nonlymphocytic leukemia.

Acyclovir: An antiviral agent used to prevent or treat herpes simplex (cold sore) and herpes zoster (chickenpox or shingles) infections that may occur when the body is immunosuppressed. May provide some weak protection against cytomegalovirus (CMV).

Adenopathy: Enlarged lymph nodes.

Adjuvant Therapy: Treatment given (when there is no clinically evident disease) in addition to the primary treatment (often surgery) to increase the chances of a cure. Adjuvant therapy may include chemotherapy, radiation therapy, or hormone therapy.

Adverse Effect: An unwanted side effect of treatment.

ALL: See Acute Lymphocytic Leukemia.

Allele: One of multiple alternate forms of a gene. Your HLA alleles determine which antigens are present on your cells. In the case of the genes that determine your tissue type (See HLA), you inherited one allele for each gene we test for from your mother and the other from your father.

Allogeneic Stem Cell Transplant: A type of transplant where the bone marrow or peripheral blood stem cells are obtained from another person, usually of the same or very similar tissue (HLA) type.

AML: See Acute Myelogenous or Non-lymphocytic Leukemia.

Analgesics: Any drug used to relieve pain. These drugs include aspirin, acetaminophen, ibuprofen, narcotics such as codeine or morphine, and topical drugs such as Novocain.

Anaplastic: Describes cancer cells that divide rapidly and have little or no resemblance to normal cells from which they were derived.

Anemia: A condition in which there is a decreased number of red cells. In severe form it results in weakness and fatigue or even fainting.

Anorexia: Loss of appetite.

Anesthesia: Loss of feeling or awareness. A local anesthetic will cause a loss of feeling in a part of your body. A general anesthetic will put you to sleep.

Antibiotics: Drugs used to treat infection usually by killing the causative germ.

Antibody: A protein substance formed by certain white blood cells in your body to help defend it against disease.

Antigen: A foreign substance that causes your immune system to create an antibody or cells that will, in turn, attack the foreign substance.

Anti-emetic: A medicine that is used to prevent or treat nausea and/or vomiting.

Apheresis: A method of obtaining and separating specific blood components, such as white blood cells (called leukopheresis), platelets, plasma, or stem cells. The process is similar to donating a unit of blood. During apheresis, a portion of the donor's blood travels through a closed, sterile tubing system through a machine that separates out the targeted cells and returns the remainder of the cells back to the donor.

Aplastic Anemia: Bone marrow failure. In this condition there is a dramatic decrease in the production of white blood cells, red blood cells and platelets leading to an increased risk of infection and bleeding. A bone marrow biopsy often shows only fat and very few normal bone marrow cells.

Aspiration: A procedure to remove fluid or material from a body area, such as removing a sample of marrow from the hip bone. This procedure is done using a needle and syringe.

Asymptomatic: No symptoms or signs of disease.

Atypical: Unusual, abnormal, or not typical.

Autologous Stem Cell Transplant: A transplant where the patient's own bone marrow or peripheral blood stem cells are removed, stored, treated and returned to the patient.

Axillary Nodes: Lymph nodes in the armpit.