Cancer is a general term for abnormal cell division and growth. This means cancer is not a single disease but many— as many as there are different types of cells in the human body. In medical terms, the 150 or so different cancers that have been found to date are grouped into five types, according to the kind of tissue in which they develop. These types are carcinoma, sarcoma, leukemia, lymphoma, and myeloma.
Carcinomas are cancers that develop in the epithelial cells that cover the skin, mouth, nose, throat, and lung airways, as well as the genitourinary and gastrointestinal (GI) tracts. They also cover glands such as the breast and thyroid. Carcinomas are tumors. The most common carcinomas are in the lung, breast, prostate, skin, stomach, and colon.
