Breast cancer is a malignant (cancerous) growth that begins in the tissues of the breast. Over the course of a lifetime, one in eight women will be diagnosed with breast cancer. Breast cancer is a cancer of the breast tissue, which can occur in both women and men. Breast cancer may be one of the oldest known forms of cancer tumors in humans.Worldwide, breast cancer is the fifth most common cause of cancer death (after lung cancer, stomach cancer, liver cancer, and colon cancer). Breast cancer kills more women in the United States than any cancer except lung cancer. Today, breast cancer, like other forms of cancer, is considered to be a result of damage to DNA. How this mechanism may occur comes from several known or hypothesized factors (such as exposure to ionizing radiation, or viral mutagenesis). Some factors lead to an increased rate of mutation (exposure to estrogens) and decreased repair (the BRCA1, BRCA2 and p53) genes. Alcohol generally appears to increase the risk of breast cancer.Breast cancer can also occur in men, although it rarely does. Experts predict 178,000 women and 2,000 men will develop breast cancer in the United States. There are several different types of breast cancer. First is Ductal carcinoma begins in the cells lining the ducts that bring milk to the nipple and accounts for more than 75% of breast cancers. Second is Lobular carcinoma begins in the milk-secreting glands of the breast but is otherwise fairly similar in its behavior to ductal carcinoma. Other varieties of breast cancer can arise from the skin, fat, connective tissues, and other cells present in the breast. Some women have what is known as HER2-positive breast cancer. HER2, short for human epidermal growth factor receptor-2, is a gene that helps control cell growth, division, and repair. When cells have too many copies of this gene, cell growth speeds up.Causes of Breast CancerSimply being a woman is the main risk for breast cancer. While men can also get the disease, it is about 100 times more common in women than in men. The chance of getting breast cancer goes up as a woman gets older. Nearly 8 out of 10 breast cancers are found in women age 50 or older. About 5% to 10% of breast cancers are linked to changes (mutations) in certain genes. The most common gene changes are those of the BRCA1 and BRCA2 genes. Breast cancer risk is higher among women whose close blood relatives have this disease. The relatives can be from either the mother’s or father’s side of the family. Woman with cancer in one breast has a greater chance of getting a new cancer in the other breast or in another part of the same breast. This is different from the first cancer coming back Many experts now believe that the main reason for this is because they have faster growing tumors. Asian, Hispanic, and American Indian women have a lower risk of getting breast cancer. Certain types of abnormal biopsy results can be linked to a slightly higher risk of breast cancer.Women who have had radiation treatment to the chest area (as treatment for another cancer) earlier in life have a greatly increased risk of breast cancerSome pregnant women were given the drug DES (diethylstilbestrol) because it was thought to lower their chances of losing the baby. Recent studies have shown that these women (and their daughters who were exposed to DES while in the uterus), have a slightly increased risk of getting breast cancer. Use of alcohol is clearly linked to a slightly increased risk of getting breast cancer. Women who have 1 drink a day have a very small increased risk. Those who have 2 to 5 drinks daily have about 1½ times the risk of women who drink no alcohol. The American Cancer Society suggests limiting the amount you drink.Being overweight is linked to a higher risk of breast cancer, especially for women after change of life and if the weight gain took place during adulthood. Also, the risk seems to be higher if the extra fat is in the waist area. Breast-feeding and pregnancy: Some studies have shown that breast-feeding slightly lowers breast cancer risk, especially if the breast-feeding lasts 1½ to 2 years. This could be because breast-feeding lowers a woman’s total number of menstrual periods, as does pregnancy. Women who began having periods early (before 12 years of age) or who went through the change of life (menopause) after the age of 55 have a slightly increased risk of breast cancer.Symptoms of Breast Cancer1.Lumps.2.Rash.3.Breast Pain.4.Cysts.5.Nipple Discharge.6.Inverted Nipple.Treatment of Breast Cancer1.Hormonal therapy (with tamoxifen).2.Chemotherapy.3.Radiotherapy.4.Surgery.