Men can also develop breast cancer and those with naturally high levels of the female hormone estrogen may be at increased risk, according to a new study. Men with the highest levels of estrogen were times more likely to develop breast cancer than men with the lowest levels of the hormone than two and a half, according to researchers. “We have shown for the first time as well as some forms of cancer in women, estrogen plays an important role in male breast cancer,” said study author Professor Tim Key of Cancer Research UK. “So now the challenge is to figure out exactly what this hormone is doing to trigger this rare form of the disease in men, and why some men have higher levels of estrogen in their blood. Our discovery is a crucial step in the Understanding the factors behind male breast cancer, “she noted.