Risk factors for breast cancer.

Breast cancer is multifaceted, and multiple risk factors most likely contribute to each case of the disease. Through further elucidation of highly penetrant autosomal dominant mutations and, perhaps more importantly, weaker polygenic influences, rational therapies to treat or prevent malignancy may develop. Determining the nature and sequence of genetic changes in premalignant breast tissue may offer the greatest opportunity to alter the process of breast cancer development.