Cancer is a group of diseases characterized by the uncontrolled growth and spread of abnormal cells. When abnormal cell growth occurs, the result can be the development of a lump, mass or tumor, which can be benign (non-cancerous) or malignant (cancerous).
Cancer comes in many forms, and the specific disease is named for the part of the body in which it begins. Cells from cancerous tumors can spread, or metastasize, throughout the body. For example, cancer that begins in the prostate but has spread to the bones is called metastatic prostate cancer. Some cancers involving the blood and blood-forming organs do not form tumors but circulate through other tissues where they grow.
To learn more about various types of cancer, click on the letters in the alpha selector above.