Objectives Pathogenic variants in homologous recombination repair (HRR) genes other than BRCA1/2 have been associated with a high risk of ovarian cancer (OC). These findings might be useful for therapeutic procedures such as PARPi. In current clinical practice, the importance of genetic testing has increased, although it is generally limited to BRCA1/2. Herein, we investigated the mutational status of both BRCA1/2 and 5 HRR genes (BRIP1, RAD51C, RAD51D, PALB2 and, BARD1) in 79 unselected OC, thus evaluating the advantage of multi-gene panel testing in the daily clinical practice.

Methods We analyzed 79 epithelial OC samples by using an NGS custom multigene panel of the 5 HRR pathways genes, beyond the genetic routine BRCA1/2 testing.

Results Overall, 21 pathogenic variants (26%) were detected. The majority (21,5%) of participants displayed a deleterious mutation in BRCA1/2, whereas 5% harboured a pathogenic variant in one of the HRR genes. Additionally, there were 15 (19%) uncertain significant variants (VUS), 5 of which occurred in BRCA1/2 and 10 of which involved at least one HRR gene. The assessment of germline mutational status showed that a little number of variants (3 pathogenic mutations in BRCA1/2 as well as 2 VUS in BRCA1 and RAD51D) were not detected in the corresponding blood sample. Notably, we unveiled 1 BRIP1 and 4 BRCA1/2 deleterious variants in the low-grade serous and endometroid histology, respectively.

Conclusions We demonstrated that the usage of a multigene panel, beyond BRCA1/2, improves the diagnostic yield in OC testing and it could produce clinically relevant results.