This just in, published in the current issue of the American Journal of Clinical Nutrition (April 2009): legumes help prevent breast cancer.
Actually, the study authors said it more like this, "Our results suggest that a diet characterized by a low intake of meat/starches and a high intake of legumes is associated with a reduced risk of breast cancer in Asian Americans".
This study, titled "Dietary Patterns and Breast Cancer Risk in Asian-American Women", looked at the diets of over 1200 women with incident breast cancer and compared them with similar women with no history of breast cancer. They made three patterns of diet to describe the diversity of food intake, a "western-meat/starch" diet, an "ethnic-meat/starch" diet, and a "vegetable/soy" diet. Women consuming a high "western-meat/starch" and low "vegetable/soy" were over twice as likely to have breast cancer in study participants.
By the way, there is no doubt in my mind that these findings apply to ALL women, regardless of their genes, since nutrition studies tend to find the same results across race and cultures.