Three or more drinks a day raised the risk by 51 percent.
Scientists believe alcohol may interfere with the metabolism of estrogen, raising the risk of getting cancer.
A major U.S. study reveals women who drink alcohol are at a greater risk of getting the most common form of breast cancer.Researchers analyzed data from more than 184,000 postmenopausal women, saying those who had one to two small drinks a day were 32 percent more likely to develop a hormone-sensitive tumor.