934 Crucial genetic variants associated with sensitivity to therapy in epithelial ovarian carcinoma patients and optimalization of digital PCR for their analysis

Introduction/Background Epithelial ovarian cancer (EOC) is seriously fatal gynecological malignancy, with especially high mortality. Next generation sequencing (NGS) allows us to characterize predictive roles of genetic profiles of EOC patients. The aim of this study was, based on our NGS data, to identify crucial genetic determinants associated with sensitivity to platinum-based EOC therapy, validate them and optimize dPCR as a technology suitable for the detection of molecular biomarkers in blood samples. Methodology Analysis of whole exome of 50 EOC and subsequent targeted sequencing of a 144 gene panel in 48 EOC tumors was used for the selection of genetic variants associated with sensitivity to platinum-based EOC therapy. Validation of key variants found in TP53, KRAS and PABPC3, was performed by PCR-based methods in 129 EOC patients and extended using large public TCGA and GENIE datasets. Optimization of dPCR methodology for detection of selected TP53 somatic variants was performed using QIAcuity machine with LNA mutation assays. Results Exome and targeted sequencing of EOC patients revealed genetic variants associated with sensitivity to EOC therapy, e.g., variants in TP53 (exons 5–10), KRAS (rs121913529, rs121913240, rs17851045) and PABPC3 (entire coding region). Candidate somatic variants in TP53 and KRAS were successfully validated and several other (eleven in TP53 and two in KRAS) revealed. TP53 mutations with the highest potential impact were selected (c.641A>G and c.818G>A) for optimization of dPCR technology in EOC patients. Conclusion Taken together, we assessed specific somatic profiles of EOC patients with potentially associated with the sensitivity to therapy. We successfully validated key variants in three genes and optimized dPCR for estimation of the most promising TP53 variants for further research. Supported by projects of the Czech Health Research Council grant no. NU22–08-00186, the Grant Agency of Charles University, projects no. 307123 and Cooperatio program no. 207035, 'Maternal and Childhood Care'. Disclosures This study was supported by running projects of the Czech Health Research Council grant no. NU22–08-00186, the Grant Agency of Charles University, projects no. GAUK 307123 and Cooperatio program no. 207035, 'Maternal and Childhood Care' by 3rd Faculty Medicine, Charles University.