Breast cancer happens when normal cells in the breast change and grow out of control. Women sometimes discover they have breast cancer because they find a lump in one of their breasts. Breast cancer is much more common in women than in men. But men can get the disease. Breast cancer sometimes runs in families.
Signs of breast cancer may include a lump in the breast, a change in breast shape, dimpling of the skin, fluid coming from the nipple, or a red scaly patch of skin.