Breast cancer usually occurs in the cells of milk-producing glands and caused due to a genetic mutation in the DNA of the breast cancer cells. It is generally diagnosed in women over 40 and above and can also affect women in younger age groups. The symptoms of breast cancer differ from person to person, but if you feel an area of thickening breast tissue or a lump in your breast, which is generally painless, or an enlarged underarm lymph node, consult your physician. Here are 5 symptoms of breast cancer