Is TP53 dysfunction required for BRCA1-associated carcinogenesis?

The identification of the breast/ovarian susceptibility genes, BRCA1 and BR CA2 was an important advancement in the field of breast and ovarian cancer research. About 40-50% of site specific hereditary breast cancers and up to 80% of hereditary breast-ovarian cancers result from mutations in the BRCA 1 gene. Although BRCA1 mediates multiple functions in the cell, including a role in DNA damage repair and gene transcription, the role of BRCA1 has no t completely been elucidated yet. It has been suggested that mutational ina ctivation of TP53 may be required for BRCA1-associated tumorigenesis. Sever al studies have shown that TP53 is more frequently inactivated in BRCA1-ass ociated tumors than in sporadic breast or ovarian cancer. Up to 90% of BRCA 1-associated tumors harbor either a TP53 mutation and/or TP53 protein accum ulation. The remaining tumors may well have other alterations affecting the cell cycle checkpoint. Loss of this checkpoint may be obligatory for BRCA1 -tumorigenesis. In this review, we discuss recent advances in BRCA1-researc h and stress the pivotal role TP53 may play in BRCA1-associated carcinogene sis. (C) 1999 Elsevier Science Ireland Ltd. All rights reserved.