The Vhl−/−;Pbrm1−/− tumours displayed solid growth patterns with prominent vasculature and were composed of cells with eosinophilic or clear cytoplasm, and increased proliferative index, features reminiscent of the histopathological appearances of human ccRCC (Fig. 5d, e and Supplementary Fig. 6d). This evidence concerns the gene PBRM1 and nonpapillary renal cell carcinoma.