Breast cancer is a type of cancer that begins in the cells of the breast. It typically forms in the ducts or lobules of the breast tissue and can spread to other parts of the body if left untreated. Breast cancer can affect both men and women, but it is more common in women. The symptoms of breast cancer may include a lump or thickening in the breast tissue, a change in the size or shape of the breast, nipple discharge, or changes in the skin over the breast. Regular screening and early detection are key to successful treatment, and there are various treatment options available depending on the stage and type of breast cancer.