Landscape of potential germline pathogenic variants in select cancer susceptibility genes in patients with adult-type ovarian granulosa cell tumors.

OBJECTIVE

The objective of this study was to assess the frequency of potential germline pathogenic variants that may contribute to risk of development of adult granulosa cell tumors (AGCT) given the paucity of germline testing guidelines for these patients.

METHODS

This was a retrospective cross-sectional study analyzing comprehensive genomic profiling (CGP) results of AGCT with the FOXL2 p.C134W mutation submitted to Foundation Medicine between 2012 and 2022. Cases with a potential germline pathogenic variant were identified by filtering single nucleotide variants and short indels by variant allele frequency (VAF) and presence in ClinVar for select cancer susceptibility genes. Odds ratios for AGCT risk were calculated compared to a healthy population.

RESULTS

Prior to analysis, 595 patients were screened and 516 with a somatic FOXL2 p.C134W mutation were included. Potential germline pathogenic variants in a DNA repair-related gene (ATM, BRCA1, BRCA2, CHEK2, PALB2, PMS2, RAD51C, or RAD51D) were found in 6.6% of FOXL2-mutated AGCT. Potential germline pathogenic CHEK2 variants were found in 3.5% (18/516) of AGCT patients, a rate that was 2.8-fold higher than Genome Aggregation Database non-cancer subjects (95% CI 1.8-4.6, p < 0.001). The founder variants p.I157T (38.9%, 7/18) and p.T367fs*15 (c.1100delC; 27.8%, 5/18) were most commonly observed. CHEK2 VAF indicated frequent loss of the wildtype copy of the gene.

CONCLUSIONS

These results support ongoing utilization of genomic tumor profiling and confirmatory germline testing for potential germline pathogenic variants. Further prospective investigation into the biology of germline variants in this population is warranted.