Somatic Variants in DNA Damage Response Genes in Ovarian Cancer Patients Using Whole-exome Sequencing

Background/Aim: Several clinical trials have investigated homologous recombination deficiency and BRCA1/2 status to select ovarian cancer patients for treatment with poly(ADP-ribose) polymerase-inhibitors (PARPi), but less attention has been given to other DNA-damage response (DDR) pathways. Therefore, we investigated somatic single/multiple nucleotide variants and small insertions/deletions in exonic and splice-site regions of 356 DDR genes to examine whether genes other than BRCA1/2 are altered. Materials and Methods: Whole-exome sequencing data from eight high-grade serous adenocarcinoma (HGSC) and four clear cell carcinoma (oCCC) patients were analyzed. Results: Forty-two variants (pathogenic, likely pathogenic or variants of uncertain significance) in 28 genes from DDR pathways were identified. Seven out of nine TP53 variants were previously described in The Cancer Genome Atlas Ovarian Cancer; other variants were found in 23 out of 28 unique genes, whereas no variants were reported in FAAP24, GTF2H4, POLE4, RPA3, and XRCC4. Conclusion: As the identified variants were not only limited to well-known TP53, BRCA1/2, and HR-associated genes, our study might contribute to the better understanding of which DDR pathways potentially influence disease progression. Moreover, they may display a potential role as biomarkers to predict platinum-based chemotherapy or PARPi treatment response or disease progression, as differences in disrupted DDR pathways were observed between patients with long and short overall survival in HGSC and oCCC groups.