A genetic mutation that raises the risk of breast cancer is found in up to 60 percent of U.S. women, making it the first truly common breast cancer susceptibility gene.
A large-scale genetic study has identified four new genes that significantly affect a woman’s risk of developing breast cancer.
The finding could allow doctors to predict cancer risk more accurately, and to guide treatments to prevent and cure the disease. But more important is what it might tell researchers about how the disease works, says Douglas Easton of the University of Cambridge, a member of the team that made the discovery. “We had no inkling that these genes had anything to do with breast cancer,” he says.
Breast cancer ? which will affect about one in every nine women in Britain and the United States ? is known to have a strong genetic influence. But until now, known genes could account for only about a quarter of the genetic component of cancer risk.
Due to the high incidence of breast cancer among older women, screening is now recommended in many countries. Screening methods suggested include breast self-examination and mammography. Mammography has been estimated to reduce breast cancer-related mortality by 20-30%. Routine (annual) mammography of women older than forty or fifty years of age is recommended by numerous organizations as a screening method to diagnose early breast cancer, and has demonstrated a protective effect in multiple clinical trials.