CD44 and nonpapillary renal cell carcinoma: In total, 14 PDEFRGs (AKR1C1, CD44, CHAC1, DPP4, FANCD2, GLS2, HMGCR, HSPB1, MT1G, NCOA4, SLC7A11, ZEB1, GOT1, and IREB2) were identified (Figure 2(d)) and were found to be significantly associated with the OS of ccRCC patients (all p < 0.05).