Breast Cancer

Breast cancer is a malignancy of the breast, usually involving the ductal or lobular tissues (the tissues involved in milk production). A small percentage of breast cancers tend to cluster in families. These cancers can be caused by mutations in particular genes, such as BRCA1 or BRCA2. In some cases, genetic syndromes involving other cancers also include an increased risk of breast cancer. Early breast cancer usually does not cause pain and may exhibit no noticeable symptoms. As the cancer progresses, signs and symptoms can include a lump or thickening in or near the breast; a change in the size or shape of the breast; nipple discharge, tenderness, or retraction (turning inward); and skin irritation, dimpling, or scaliness. These changes can also be caused by conditions other than breast cancer. Breast cancers caused by inherited gene mutations tend to occur earlier in life than sporadic (noninherited) cases and are more likely to involve both breasts.