Cancer

Cancer, often thought of as a single disease, is actually a group of diseases in which abnormal cells divide without control and are able to invade other tissues. Cells are the basic structure of the body and are specific to their location and function—for example heart cells and kidney cells; they carry out their functions, divide, and die in an orderly, controlled way. This happens in response to the body’s need to grow, maintain, renew, and repair itself. Cancer cells, however, look different and do not behave the same as normal cells.

The process for which normal cells are programmed to carry out their functions, stop dividing, and die is called apoptosis, or programmed cell death. Cancer cells ignore the signals that normally tell cells to ...