Meta-analysis and single-center experience on the comprehensive genomic characterization and landscape of BRCA1 and BRCA2 in Turkey.

Abstract

e13611 Background: The detection of BRCA1 and BRCA2 mutations both somatic and germ-line became essential for the clinical management strategies of different cancers. Aiming at the identification of common and recurrent mutations that answer the questions about the association between a variant and phenotype, we collected the data of 1126 probands with pathogenic, likely pathogenic variants and variants of uncertain significance (VUS) distributed across 22 Turkish cities. Methods: Peripheral blood samples from 1126 individuals were collected and sequenced via the GeneReader (Qiagen, Hilden, Germany) and MiSeq (Illumina, San Diego, USA) NGS systems for BRCA1/ BRCA2 genes. QCI-Analyze and QCI-Interpret bioinformatics tools were used for bioinformatics analyses. Results: Total of 68 and 108 distinct variants were identified in BRCA1 and BRCA2 genes, respectively. Twenty novel variants were identified in both genes, while BRCA2 had higher heterogeneity. However, there had been no any recurrent mutations identified in any certain geographic region. Among all distinct mutations identified 11.9% were novel, corresponding to 12.8% of all carriers and 28.4% were VUS, corresponding to 32.1% of all carriers. Conclusions: This study presented with three important outcomes. First, a significant molecular heterogeneity in BRCAs among Turkish carriers were confirmed with 15.63% positivity rate. Most notably as the second, this is the first study showing the profiles of recurrent and common mutations that might be unique to Turkish landscape. In conclusion, it is critical to identify all the genetic variants, to aid in diagnosis, prevention, prognosis and treatment. Third and the last, the identification of novel mutations in BRCAs is a vital information that should be shared with mutation databases, in order to use for further clinical interpretation of Turkish population. Key words: Landscape of BRCA1/2, genetic testing, BRCA profiling, population data.