Breast cancer is the development of abnormal cells in the breast. These cells grow and replace normal healthy tissue. About one in eight women develop breast cancer.
Men also can have breast cancer although it is much less common in men.
However, surgery may involve removing all of the breast. When abnormal cells grow uncontrollably, they are called cancers. It is not known why many cancers occur. Some women are more likely to have breast cancer than others. You have never breast-fed a baby or you had your first child after age 30.