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Background Clear cell renal cell carcinomas (ccRCC) frequently display a loss of function of the von Hippel–Lindau ( VHL ) gene. Objective To elucidate the putative relationship between VHL mutation status and immune checkpoint ligand programmed death-ligand 1 (PD-L1) expression. Design, setting, and participants A series of 32 renal tumors composed of 11 VHL tumor-associated and 21 sporadic RCCs were used to evaluate PD-L1 expression levels after sequencing of the three exons and exon–intron junctions of the VHL gene. The 786-O, A498, and RCC4 cell lines were used to investigate the mechanisms of PD-L1 regulation. Outcome measurements and statistical analysis Fisher's exact test was used for VHL mutation and Kruskal–Wallis test for PD-L1 expression. If no covariate accounted for the association of VHL and PD-L1, then a Kruskal–Wallis test was used; otherwise Cochran–Mantel–Haenzsel test was used. We also used the Fligner–Policello test to compare two medians when the distributions had different dispersions. Results and limitations We demonstrated that tumors from ccRCC patients with VHL biallelic inactivation (ie, loss of function) display a significant increase in PD-L1 expression compared with ccRCC tumors carrying one VHL wild-type allele. Using the inducible VHL 786-O-derived cell lines with varying hypoxia-inducible factor-2 alpha (HIF-2α) stabilization levels, we showed that PD-L1 expression levels positively correlate with VHL mutation and HIF-2α expression. Targeting HIF-2α decreased PD-L1, while HIF-2α overexpression increased PD-L1 mRNA and protein levels in ccRCC cells. Interestingly, chromatin immunoprecipitation and luciferase assays revealed a direct binding of HIF-2α to a transcriptionally active hypoxia-response element in the human PD-L1 proximal promoter in 786-O cells. Conclusions Our work provides the first evidence that VHL mutations positively correlate with PD-L1 expression in ccRCC and may influence the response to ccRCC anti-PD-L1/PD-1 immunotherapy. Patient summary We investigated the relationship between von Hippel–Lindau mutations and programmed death-ligand 1 expression. We demonstrated that von Hippel–Lindau mutation status significantly correlated with programmed death-ligand 1 expression in clear cell renal cell carcinomas. [ABSTRACT FROM AUTHOR]

• Inherited predisposition to renal cell carcinoma (RCC) is of great importance. • A dozen of RCC predisposing genes have been discovered yet. • Study of an atypical family presenting with three different histological renal tumors: an angiomyolipoma, a clear-cell RCC and an oncocytic papillary RCC. • Identification by exome sequencing of the first germline mutation in the Neighbor of BRCA1 gene 1 (NBR1) involved in autophagy. • The mutation may have a dominant negative effect. Hereditary Renal Cell Carcinomas (RCC) are caused by mutations in predisposing genes, the major ones including VHL, FLCN, FH and MET. However, many families with inherited RCC have no germline mutation in these genes. Using Whole Exome Sequencing on germline DNA from a family presenting three different histological renal tumors (an angiomyolipoma, a clear-cell RCC and an oncocytic papillary RCC), we identified a frameshift mutation in the Neighbor of BRCA1 gene 1 (NBR1), segregating with the tumors. NBR1 encodes a cargo receptor protein involved in autophagy. Genetic and functional analyses suggested a pathogenic impact of the mutation. Indeed, functional study performed in renal cell lines showed that the mutation alters NBR1 interactions with some of its partners (such as p62/SQSTM1), leading to a dominant negative effect. This results in an altered autophagic process and an increased proliferative capacity in renal cell lines. Our study suggests that NBR1 may be a new predisposing gene for RCC, however its characterization needs to be further investigated in order to confirm its role in renal carcinogenesis. [ABSTRACT FROM AUTHOR]