The BRCA1 protein presents a paradox to the scientists investigating its link to cancer. BRCA1 provides a function essential to all cell types, but its mutation is only associated with a subset of cancers including breast and ovarian cancers. The priorities of BRCA1 research are the identification of the function of BRCA1, which is required in all cells, and of the function specific to breast and ovarian cells that causes their cancerous transformation. BRCA1 has been shown to be required for multiple processes including transcription, chromatin remodeling, DNA damage repair, and the regulation of centrosome duplication. How BRCA1 regulates these processes is unclear: is the BRCA1 protein a direct participant in the biochemistry of each process, or is the BRCA1 protein regulating the gene expression of proteins that directly regulate all of these processes? The ubiquity of BRCA1 in multiple cellular processes is difficult to square with the specificity of tumors with which it is associated.