Frequency of pathogenic germline variants in cancer susceptibility genes in 841 renal cell carcinoma cases

e16551 Background: Hereditary Renal cell carcinoma (RCC) syndrome accounts for approximately 5-10% of all kidney cancers. However, the genetic architecture of susceptibility to RCC is not well defined. In this study, we investigated the prevalence and spectrum of pathogenic/likely pathogenic germline variants of cancer susceptibility genes in unselected RCC patients in the real-world Chinese population. Methods: We retrospectively profiled the germline mutations of 841 unselected RCC patients using a next-generation sequencing panel consisting of 808 cancer-related genes. Interpretation of sequence variations was classified according to the American College of Medical Genetics and Genomics guidelines. Genomic alterations include single nucleotide variations (SNV), short insertions/deletions (INDEL) and copy number variations (CNV). Results: Within 841 unselected RCC patients included in this study, 132 germline pathogenic/likely pathogenic (P/LP) variants were identified in 125 patients (14.9%), of which 114 (13.6%) were mutations of SNV/INDEL and 11 (1.3%) were CNV. Overall, 46 patients (5.5%) carried mutations of hereditary RCC syndrome-associated genes such as VHL (13, 1.5%), FH (13, 1.5%) and FLCN (8, 1.0%). Interestingly, variants in other cancer-predisposition genes not traditionally associated with RCC occurred in 9.4% of the unselected series, including 55 (6.5%) patients carried mutations in DNA damage (DDR)-related genes (e.g., MUTYH, CHEK2 and BRCA1/2) and the other 24 (2.9%) had germline mutations of non-DDR-related genes (e.g., SPINK1 and APC). The median age of patients with mutations of RCC syndrome-associated genes was 38 (range 19-77), while the median age of patients with mutations of other cancer-predisposition genes was 52(range 22-82). Furthermore, in patients older than 46 years, the prevalence of P/LP variants in RCC-associated and non–RCC-associated genes were 1.9% and 6.7%, respectively. Notably, among 125 patients with identified germline mutations, nearly half (56, 44.8%) did not meet the recommended criteria for genetic testing. Conclusions: Our findings confirm a high prevalence of pathogenic germline variants in genes associated with both hereditary RCC and other cancer predispositions in the unselected Chinese RCC population. Current guidelines recommendation for genetic testing seemed not sensitive enough to identify patients with hereditary RCC susceptibility. It is rational to promote genetic testing and expand the range of genes in RCC population with advanced age.