PBRM1 and nonpapillary renal cell carcinoma: Among the top 8 frequently mutated genes (VHL, PBRM1, BAP1, SETD2, KDM5C, PTEN, MTOR, TP53) in ccRCC in the COSMIC database, which also represent the eight most significantly mutated genes in the TCGA database, six were verified in our study, including VHL (67%), PBRM1 (7%), BAP1 (13%), SETD2 (13%), PTEN (7%) and MTOR (7%) (Fig. 6).