CDKN2A and nonpapillary renal cell carcinoma: The top 5 up-regulated FRGs in ccRCC were IFNG, ALOX15B, CDKN2A, HILPDA and CA9, while the top 5 down-regulated FRGs in ccRCC were PROM2, SLC2A12, MT1G, ACSF2 and PSAT1.