But not all tumors are cancer. A tumor that is not cancer is called benign. Benign tumors do not grow and spread the way cancer does. They are usually not a threat to life. Most kinds of cancer are named after the part of the body where the cancer first starts.
Breast cancer begins in the breast tissue.
This article refers only to breast cancer in women. Men can also get breast cancer, although this is rare. A separate document on male breast cancer is available from the American Cancer Society. Inside the breasts are glands that produce and release milk after a woman has a baby. The glands that make the milk are called lobules and the tubes that connect them to the nipple are called ducts.