Germline mutations in the BRCA1 tumor suppressor gene predispose women to ovarian and breast cancer, and in men are associated with the development of prostate cancer. The cyclin D1 gene encodes a component of a pRb kinase, which is frequently overexpressed in human breast cancer and is considered a collaborative oncogene. Wang et al. demonstrate that cyclin D1 antagonizes BRCA1-mediated repression of estrogen receptor α(ERα)-dependent gene expression independently of its kinase function. The cover features a confocal microscopy for BRCA1 (green) and ERα (red) in MCF-7 cells,showing colocalization (yellow) in nuclear dots. As cyclin D1 is induced by oncogenic and mitogenic signals in breast cancer cells, these findings may represent a general mechanism by which diverse oncogenes block BRCA1 tumor suppressor function. For details, see the article by Wang et al. on page 6557 of this issue.