Immunohistochemical analysis (IHC) of 90 ccRCC and adjacent normal kidney tissues using anti-PBRM1 and anti-Tryptase (specific marker of mast cells) antibodies showed that PBRM1 protein expression was significantly reduced in the ccRCC tissues compared to the adjacent kidney tissues (Figure 4A, 4B, P<0.001). The gene discussed is PBRM1; the disease is nonpapillary renal cell carcinoma.