Peripheral blood DNA methylation detected in the BRCA1 or BRCA2 promoter for sporadic ovarian cancer patients and controls

Background: Ovarian cancer is located at the fifth rank of female cancers. Different risk factors including genetic factors with BRCA1 and BRCA2 genes played an important role in the etiology of the ovarian cancer. In most of sporadic ovarian cancer, variation in the expression of BRCAI and BRCA2 genes was observed and it could be a consequence of epigenetic modifications. This work aimed to study methylation at CpG islands within the promoter of the BRCA1 and BRCA2 genes in sporadic ovarian cancers. Methods: For this, we conducted a case-control study consisted of 51 ovarian cancer cases with no BRCA mutation and 349 healthy women. All participants came from the Auvergne region in France. Genomic DNA was extracted from peripheral blood cells (PBCs) and we used the Quantitative Analysis of Methylated Alleles (QAMA) to estimate the per cent of methylation in the BRCA1 and BRCA2 promoters. Results: BRCA1 methylation is significantly decreased in ovarian cancer by comparison with the control group. The comparison between the two different populations did not show any significant difference regarding BRCA2 methylation but exhibited a trend in the decrease of BRCA2 promoter methylation in peripheral blood DNA of sporadic ovarian cancer. Conclusions: These results may have implications in better understanding the underlying epigenetic mechanisms in BRCA1 and BRCA2 oncosuppressors in sporadic ovarian cancer. (C) 2011 Published by Elsevier B.V.