Each year, more than 180,000 women in this country learn they have breast cancer. Cancer is a group of diseases which occur when cells become abnormal and divide without control or order. Every organ in the body is made up of various kinds of cells.
Cells normally divide in an orderly way to produce more cells only when they are needed.
This process helps keep the body healthy. If cells divide when new cells are not needed, they form too much tissue. The mass or lump of extra tissue, called a tumor, can be benign or malignant. Benign tumors are not cancer. They can usually be removed, and in most cases, they don't come back.