From our TCGA data analysis, we found that in ccRCC samples, RAB25 (Delta Beta = 0.202, Methylation FDR = 1.080E-56, mRNA FDR = 1.180E-38, log2 FC = −3.505) and CYP4B1 (Delta Beta = 0.314, Methylation FDR = 1.600E-48, mRNA FDR = 4.070E-05, log2 FC = −1.836) are both downregulated with promoter hypermethylations and CA9 is upregulated with promoter hypomethylation (Delta Beta = 0.220, Methylation FDR = 6.790E-61, mRNA FDR = 2.350E-211, log2 FC = 5.836). The gene discussed is CA9; the disease is nonpapillary renal cell carcinoma.