Women with certain gene mutations are more likely to develop breast cancer if they were exposed to radiation from chest X-rays or mammograms before age 30, compared with those who have the gene mutations and weren't exposed to radiation, new research suggests. The study included nearly 2,000 women, 18 and older, in the Netherlands, France and the United Kingdom. All of the women had a mutation in the BRCA1 or BRCA2 genes, which have long been linked to raised risks for breast and ovarian cancer. Forty-eight percent of the women reported ever having an X-ray and 33 percent had undergone...