About Breast Cancer

is cancer that affects the breast. The vast majority of breast cancer occurs in women, although men can develop breast cancer too. 'Cancer' is the name for a group of diseases in which the body's cells are changed in appearance and function. Such abnormal cells can grow out of control and form a mass or 'tumor.' When abnormal cells originate in the breast tissue, the mass is called a breast tumor. A breast tumor is considered benign if it is limited to a few cell layers and does not invade surrounding tissues or organs. Yet if the tumor spreads to surrounding tissues or organs, it is considered malignant, or cancerous. Carcinoma is the term used to describe most common cancers that arise from epithelial (surface or lining) tissues. By contrast, sarcoma is the term used to define tumors that arise from bone, muscle, fat, or connective tissues. The breasts are, in essence, a collection of fatty tissues and glands that have been adapted to secrete milk after a woman gives birth. The glands that produce milk are called lobules and the tubes that connect them to the nipples are called ducts. Correspondingly, carcinoma of the breast develops when malignant changes occur in the cells that line the lobules or, more commonly, the ducts.