In search of the tumour-suppressor functions of BRCA1 and BRCA2

Hereditary breast and ovarian cancer syndromes can be caused by loss-of-fun ction germline mutations in one of two tumour-suppressor genes, BRCA1 and B RCA2 (ref. 1). Each gene product interacts with recombination/DNA repair pr oteins in pathways that participate in preserving intact chromosome structu re. However, it is unclear to what extent such functions specifically suppr ess breast and ovarian cancer. Here we analyse what is known of BRCA gene f unction and highlight some unanswered questions in the field.