Breast Cancer is the cancer that develops in the breast tissue. It is the most common infiltrating cancer in females worldwide. It generally starts in the inner lining of milk lobules or the ducts that supply milk. Cancer arising in the milk lobules is known as lobular carcinoma whereas the cancer that develops in the milk ducts is known as ductal carcinoma. Obesity, lack of physical exercise, alcohol consumption, hormone replacement therapy and family history are the major causes of breast cancer. Females are more prone to breast cancer compared to males. Breast cancer accounts for 16% of cancers in females and 23% of invasive cancers. 18% of cancer deaths worldwide are due to breast cancer in both the genders. 5-10% of breast cancers are hereditary. One in every eight women in USA develops breast cancer in sometime of her life. Breast cancer is more common in white women but the mortality rate due to this cancer is more in black women.