Breast cancer is a malignant tumor that forms in the cells of the breast. Although mostly found in women, men can get breast cancer too. There are a number of symptoms associated with breast cancer, but the first noticeable symptom is often a lump or area of thickened breast tissue. A lump in the breast does not necessarily mean you have cancer - most breast lumps are not cancerous. However, it is always best to have them checked by your doctor. Treatment for breast cancer may include surgery, radiation, chemotherapy, hormone therapy, targeted therapy or bone-directed therapy.