BRCA1 and ovarian cancer: Recent studies by Clark-Knowles and colleagues showed conditional knockout of the Brca1 gene in the OSE of FVB mice, led to an increase in preneoplastic changes in ovarian biology, including OSE invagination, epithelial cell hyperplasia and small inclusion cysts, but did not give rise to ovarian cancers, up to 8 months after inactivation of Brca1 in the OSE [20].