Glossary of Cancer Terms

B cells

A type of white blood cell. Many B cells mature into plasma cells.

Bacillus calmette-guerin (BCG)

A substance that activates the immune system. A form of biological therapy. Used commonly as intravesical (in the bladder) therapy for bladder cancer.

Barium solution

A liquid containing barium sulfate that is used in x-rays to highlight parts of the digestive system.

Basal Cell Cancer Basal cell cancer is the most common form of skin cancer. It develops in the outermost level of the skin. It can appear as a flesh colored translucent nodule, a blue, black, or brown lesion, or a red scaly localized plaque that may bleed. It is treated most often with local surgery.

Basal cells

Small, round cells found in the lower part, or base, of the epidermis, the outer layer of the skin.

Base pairs

Two complementary, nitrogen-rich molecules held together by weak chemical bonds. Two strands of DNA are held together in the shape of a double helix by the bonds between their base pairs.



Not cancerous, does not invade nearby tissue or spread to other parts of the body.

Benign breast changes

Non-cancerous changes in the breast. These can include pain, lumpiness, nipple discharge.

Benign Prostatic Hyperplasia

A benign condition in which an overgrowth of prostate tissue pushes against the urethra and the bladder, blocking the flow of urine. Also called benign prostatic hypertrophy or BPH.


Human choices or any other factors beside the treatments being tested that affect a study’s results. Clinical trials use many methods to avoid bias, because biased results may not be correct.

Bile duct The bile ducts are tubes that connect the liver and the gallbladder to the small intestine. Bile is manufactured in the liver and helps with the digestion of fats.
Bile Duct Cancer Also called cholangiocarcinoma. Bile duct cancer is a rare cancer. Since bile ducts are located throughout the liver, bile duct cancer can ocurr in many locations in and around the liver.


A method of learning to control certain body functions such as heartbeat, blood pressure, and muscle tension with the help of a special machine. This method can help control pain.

Biological response modifiers (BRM)

Substances that stimulate the body’s response to infection and disease.

Biological therapy

Treatment to stimulate or restore the ability of the immune system to fight infection and disease. This treatment can also be used to lessen side effects caused by other cancer treatments. This is also known as immunotherapy, biotherapy or biological response modifier (BRM) therapy.


A procedure used to remove cells or tissue to determine a diagnosis. The cells or tissue are sent to a pathologist to be interpreted.

Bladder The bladder is a hollow organ in the lower abdomen that stores urine. The kidneys filter waste from the blood and produce urine, which enters the bladder through two tubes called ureters. Urine leaves the bladder through another tube, the urethra.
Bladder Cancer Cancer which develops in the bladder. Transitional cell is the most common type of bladder cancer.

Blast phase

Refers to advanced chronic myelogenous leukemia. In this phase, the number of immature, abnormal white blood cells in the bone marrow and blood is extremely high. Also called blast crisis.


Immature blood cells.

Blood count

Measurement of the number of red cells, white cells, and platelets in a sample of blood.

Blood-brain barrier

A protective network of blood vessels and cells that filters blood flowing to the brain.

Bone Cancer

Cancers that start in the bone are called sarcomas. There are several types of sarcoma. Each type begins in a different kind of bone tissue. The most common are osteosarcoma, Ewing's sarcoma, and chondrosarcoma. Cancers that begin in the bone are quite rare. It is not unusual for other types of cancer to spread to the bone. When this happens, the disease is not called bone cancer.

Bone marrow

The soft, spongy tissue in the center of bones. Marrow 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 to evaluate for abnormalities.

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 cancer or by treatment with high doses of anticancer drugs or radiation. Transplantation may be autologous (the person’s own tissue) allogeneic (marrow donated by another person), or syngeneic (marrow donated by an identical twin).

Bone scan

A technique to create images of bone on a computer screen or on film. A small amount of radioactive material is injected and travels through the bloodstream. It collects in the bones, especially in abnormal areas of the bones, and is detected by a scanner.


Radioactive material sealed in needles, seeds, wires, or catheters is placed directly into or near the tumor. Also called internal radiation, implant radiation, or interstitial radiation therapy.

Brain Cancer Malignant brain tumors contain cancer cells. They interfere with vital functions and are life threatening. Malignant brain tumors can grow rapidly and invade the tissue around them. Like a plant, these tumors may put out "roots" that grow into healthy brain tissue. If a malignant tumor remains compact and does not have roots, it is said to be encapsulated. When an otherwise benign tumor is located in a vital area of the brain and interferes with vital functions, it may be considered malignant (even though it contains no cancer cells).

Brain stem

The stemlike part of the brain that is connected to the spinal cord.

BRCA1 and BRCA2 genes

The principal genes that, when altered, indicate inherited susceptibility to breast cancer. These gene alterations are present in 80-90% of hereditary cases of breast cancer, but represent only 4-6% of all breast cancer.

Breakthrough pain

Occurs when moderate to severe pain, that is well controlled “breaks through” or is felt for a short time.

Breast Cancer Breast cancer is diagnosed with self- and physician-examination of the breasts, mammography, ultrasound testing, and biopsy. There are many types of breast cancer that differ in their capability of spreading to other body tissues (metastasis). Treatment of breast cancer depends on the type and location of the breast cancer, as well as the age and health of the patient.

Breast Cancer in Situ

Very early or non-invasive abnormal cells that are confined to the ducts or lobules in the breast. Also known as DCIS or LCIS.

Breast implants

Silicone rubber sacs filled with salt water or silicone gel. Used for breast reconstruction after mastectomy.

Breast reconstruction

Surgery to rebuild a breast’s shape after mastectomy.

Breast-conserving surgery

An operation to remove breast cancer, but not the breast itself. Types of breast-conserving surgery include lumpectomy (removal of the lump), segmental mastectomy (removal of the cancer and some surrounding breast tissue and the lining over the chest muscles below the tumor.

Buccal mucosa

The inner lining of the cheeks and lips.


An operation in which the doctor creates a new pathway for the flow of body fluids.


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