The role of caveolae and the caveolin proteins in cancer has been the subject of extensive research. BRCA1 participates in multiple biological pathways including DNA damage repair, transcriptional control, cell growth, apoptosis, and others. Little information, however, is available regarding the cellular mechanisms that control BRCA1 gene expression. The present study examined the potential regulation of BRCA1 gene expression and subcellular localization by Cav-1. Results of Western blots, RT-PCR, and transfection experiments showed that Cav-1 enhances BRCA1 protein and mRNA levels via a mechanism that involves transactivation of the BRCA1 promoter and which is p53-dependent. In addition, immunostaining experiments demonstrate that Cav-1 induced the cytoplasmic sequestration of BRCA1.