PBRM1 and nonpapillary renal cell carcinoma: Analysis of sequencing data revealed that genes commonly mutated in ccRCC, including VHL (10/12 patients) and PBRM1 (8/12 patients), are the two most frequently mutated genes, indicating that our ccRCC samples have a mutational profile consistent with other large tumor genome sequencing studies such as TCGA KIRC [14] (Additional file 1: Table S3).