Comprehensive BRCA mutation analysis in the Greek population. Experience from a single clinical diagnostic center

Germline mutations in the BRCA1 and BRCA2 genes are associated with hereditary predisposition to breast and ovarian cancer. Sensitive and accurate detection of BRCA1 and BRCA2 mutations is crucial for personalized clinical management of individuals affected by breast or ovarian cancer, and for the identification of at-risk healthy relatives. We performed molecular analysis of the BRCA1 and BRCA2 genes in 898 Greek families, using Sanger sequencing or Next Generation Sequencing for the detection of small insertion/deletion frameshift, nonsynonymous, truncating and splice-site alterations and MLPA for the detection of large genomic rearrangements. In total, a pathogenic mutation was identified in 12.9% of 898 families analyzed. Of the 116 mutations identified in total 9% were novel and 14.7% were large genomic rearrangements. Our results indicate that different types of mutational events in the BRCA1 and BRCA2 genes are responsible for the hereditary component of breast/ovarian cancer in the Greek population. Therefore the methodology used in the analysis of Greek patients must be able to detect both point and small frameshift mutations in addition to large genomic rearrangements across the entire coding region of the two genes.