In addition, according to the oncogene Nicotinamide N-Methyltransferase (NNMT) in ccRCC, we found that renal tubule cells, endothelial cells in ccRCC tissues high-expressed NNMT, while the two types of cells in para-tumor tissues barely expressed NNMT (Supplementary Fig. 2). Here, NNMT is linked to nonpapillary renal cell carcinoma.