Metastasis Health Article

Angiogenesis

—The process of forming new blood vessels that supply a tumor with nutrients and help to carry tumor emboli into the larger vessels of the circulatory system.

Apoptosis

—The programmed self-destruction of a cell, which takes place when the cell detects some damage to its DNA. Apoptosis is sometimes called "cell suicide."

Basement membrane

—A specialized layer of extra-cellular matrix that separates epithelial tissue from underlying connective tissue. Cancer cells must break through the basement membrane in order to migrate to other parts of the body and form metastases.

Embolus (plural, emboli)

—A clump of tumor cells that breaks off from a primary tumor to travel through the circulatory system and lodge in a capillary in another part of the body. The process of forming emboli is called embolization.

Epithelium

—The layer of tissue that covers body surfaces and lines the internal surfaces of body cavities, blood vessels, and hollow organs. Most cancer cells arise within epithelial tissue.

Extracellular matrix

—A collection of connective tissue proteins and fibers that supports and nourishes body tissues. The extracellular matrix forms a physical barrier to the movement of tumor cells.

Extravasation

—The process of reverse invasion in which tumor cells that have invaded the blood vessels and traveled to other organs force their way back out of the blood vessels and into the tissues surrounding their new site.

Micrometastasis (plural, micrometastases)

—A term sometimes used to describe malignant tumor cells circulating in the blood or other metastases too small to be detected by a standard clinical examination.

Multicentric

—A type of cancer that appears at several different sites in the patient's body simultaneously.

Oncogene

—Any gene that is a factor in triggering the development of cancer. Oncogenes are mutated forms of proto-oncogenes, which are genes that promote the normal process of cell growth and division.

Replication

—The process in which a cell duplicates or copies itself.

Tumor markers

—Substances that occur in the blood, urine, or tissues of patients with certain types of cancer. Tumor markers may be produced either by the tumor itself or by the body in response to the tumor.

Tumor necrosis factor (TNF)

—A protein that destroys cells showing abnormally rapid growth. TNF is used in immunotherapy to shrink tumors rapidly.

Tumor suppressor gene

—A gene that encodes proteins that inhibit cell division and replication. Tumor suppressor genes are damaged or inactive in many types of cancer cells.

Vascular endothelial growth factor (VEGF)

—A substance released by tumor cells that attracts vascular (blood vessel) cells to the tumor. The vascular cells then form new blood vessels within the tumor.

Vascularization

—Another name for angiogenesis.