BRCA1/2 mutations represent first genetically defined predictive markers for targeted therapy of patients with recurrent high-grade serous carcinoma (HGSC), therefore patients with HGSC should be tested for a germline and somatic BRCA mutation (gBRCAm and sBRCAm, resp.). In our study we analyzed possibilities and limits for determination of both origin and pathogenicity of mutations detected by HGSC biopsies analyses.
We present data obtained by massive parallel sequencing on Miseq (Illumina). Library for sequencing was prepared by Somatic BRCA MASTR Plus kit (Multiplicom) from DNA isolated from HGSC FFPE tissue of 42 patients allowing simultaneous identification of gBRCAm and sBRCAm. For the pathogenicity evaluations we followed American College of Medical Genetics and Genomics (ACMG) criteria and used various bioinformatic tools.
All sequencing data were interpreted by SOPHIA DDM (Sophia Genetics) commercial tool. BRCA1/2 mutation was absent in 43 % and present in 50 % of patients, while 7 % of cases had to be retested due to low coverage. Data of 28/42 patients were analyzed also by Ingenuity (Qiagen), the comparison of both the tools identified discrepant pathogenic determinationin 29 % of them. The discrepancies in origin and pathogenicity of already detected mutations were found also by analyzing the data in other non-commercial databases (dbSNP, COSMIC, ClinVar, BIC, etc.).
At least in a certain proportion of the cases, the data obtained by HGSC biopsy specimen mutational analyses and interpreted by accessible bioinformatic tools may lead to an equivocal assessment of both origin and pathogenicity of detected BRCA1/2 mutations. Other studies are necessary to eliminate the observed discrepancies.
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