PBRM1 and nonpapillary renal cell carcinoma: Although most ccRCC cell lines with damaging PBRM1 mutations have poor engraftment rates as subcutaneous tumors in nude mice (27), we identified one cell line, OS-RC-2, which harbors a missense mutation in the PBRM1 bromodomain as a potential system to model PBRM1 loss in vivo (27).