PECAM1 and nonpapillary renal cell carcinoma: In our study, the expression levels of BNIP3, CCND1, ERBB2, and PECAM1 were significantly negatively correlated with infiltration level of Treg cells, and CEBPB, TIMP1, and UBE2C were positively associated with infiltration level of Treg cells, suggesting that these genes might affect ccRCC patients’ prognosis through regulating infiltration of Treg cells.