Comparative Cancer Center

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Linear Accelerator

Guide to Cancer Terms

Cancer Terms/ Glossary

Adenoma: A benign tumor of glandular tissues, skin and other tissues that cover some organs; e.g., sebaceous gland adenoma. 

Anaplasia: The term implies loss of cellular differentiation or organization.

Angiogenesis: The formation of new blood vessels.  This process is required for tumor growth.

Apoptosis: One of the two major mechanisms by which cells die (necrosis is the other major method), apoptosis, or “programmed cell death” is a mode of cell death in which single cells are deleted in the midst of living tissue without causing inflammation.

Cancer: (Crab): Any malignant neoplasm (tumor).

Carcinogen: Any cancer causing or promoting substance.  These can be chemicals, radiation or other substances that cause damage to DNA.

Carcinoma: A malignant tumor derived from epithelium, or tissue that covers/lines  organs or the skin.  e.g.Squamous cell carcinoma originates from stratified squamous epithelium. Transitional cell carcinoma arises from transitional epithelium of the urinary tract. Adenocarcinoma is a carcinoma of glandular epithelium and includes malignant tumors of the GI mucosa, skin, and other sites. 

Carcinoma in situ: An epithelial tumor showing non-invasion of mesenchymal tissue. The term is synonymous with intraepithelial or pre-invasive carcinoma. The abnormal cells do not infiltrate below the basement membrane of the tissue. These terms are generally limited to lesions of epithelial origin. Although pre-invasive lesions may normally show some cytomorphologic features of malignancy, they lack one cardinal feature— invasiveness.

Chemotherapy: Drug(s) used to kill cancer cells.

Differentiation: The process of cellular maturity and organization characteristic of normal tissues.

Dysplasia: An abnormal cellular proliferation in which there is loss of normal architecture and orientation—often associated with chronic, protracted irritation and inflammation. This term is also used in the context of a preneoplastic or “precursor” lesion. 

Germ cell tumor: Cancer that develops in ovaries or testes, e.g., ovarian dysgerminoma, testicular seminoma.

Grade: A histological classification of a tumor designed to estimate the biologic behavior of the tumor.  Generally the higher the grade the more aggressive the tumor.  Grade is assigned based on microscopic criteria including: mitotic index, hemorrhage, necrosis, invasiveness. 

Hamartoma: A tumor-like malformation composed of a mixture of adult tissues usually present in the part; a tumor-like nodule of superfluous tissue.

Hyperplasia: An increase in the size of an organ or tissue due to increase in number of cells. It may be physiologic, compensatory or pathologic; e.g., lymphoid hyperplasia.

Hypertrophy: An increase in the size of an organ or tissue due to increase in cell size (not cell number), for example, in skeletal muscle.

Leukemia: Cancer that develops in blood cells or blood-forming tissues—bone marrow and spleen.

Lymphoma: Cancer that develops in cells of lymph nodes.

Metastasis: Secondary, discontinuous deposit of malignant neoplasm. The spread of cancer cells to other areas of the body originating from the primary tumor.

Mixed tumor: A complex tumor of epithelial and mesenchymal elements, usually encountered in veterinary medicine in neoplasms derived from the mammary or salivary glands.

Myeloma: Cancer that develops in antibody-forming blood cells, plasma cells, and in the bone marrow of the pelvis, spine, ribs and skull, i.e., multiple myeloma.

Neoplasm (neoplasia): (Neos = new, plasma = anything formed, a growth). A new growth; an aberrant proliferation of cells; may be benign or malignant.

Oncogenes: Genes that play a role in normal cell growth and differentiation (protooncogenes) but that can mutate (oncogenes) and cause the uncontrolled cell growth associated with cancer, e.g., c-myc, c-ras.

Osteosaroma: A malignant tumor that is derived from bone.

Papilloma: A benign tumor derived from surface epithelium.

Prognosis: Predicting outcome.

Radiotherapy: The use of radiation in the treatment of cancer.

Sarcoma: Fleshy tumor—a malignant tumor derived from mesenchymal tissues, e.g., fibrosarcoma.

Stage: A clinical method used to estimate the extent of spread of cancer. 

Stem cell: Subpopulations of tumor cells with extensive proliferative capacity. 

Tumor suppressor genes: Genes (i.e., p53, Rb) that exist in normal cells to control cell growth. Some tumors may occur when mutations or deletions occur in these genes, allowing uncontrolled cell growth.

Teratoma: A true tumor arising from multipotential embryonic cells and hence composed of tissues of tridermal origin foreign to the site of origin.

Tumor: In clinical medicine, the term tumor and neoplasia are often used interchangeably, although tumor literally refers only to a distinct, palpable lump or swelling.