A paper in PNAS this week looks at how mutations in genes associated with breast cancer affect BRCA1, a tumor suppressor gene that when mutated leads to breast, ovarian, and prostate cancers. Analyzing data from NCI's CGEMS project on 18 breast cancer-related genes, statisticians from Columbia and Harvard found that there are "many interesting interactions" between BRCA1 and other genes, suggesting that mutations in these genes maybe predispose people to cancer even if they don't carry usual BRCA1 mutations known to cause cancer.