Interestingly, the mRNA expression level of SEMA6A was also significantly correlated with both CCND1 and NDRG1 (Fig. 2D, E), two known HIF-2α target genes, suggesting that SEMA6A is associated with the HIF-2α signaling pathway in ccRCC. This evidence concerns the gene NDRG1 and nonpapillary renal cell carcinoma.