DPP4 and chromophobe renal cell carcinoma: Thus, the relative expression of DPP4 (DPP IV transcriptome) and MME (NEP transcriptome) genes were found to be strongly decreased in ChRCC samples (DPP IV: ↓ fortysixfold, NEP: ↓ sixtysevenfold; tumor vs normal) and, although no statistically significant, slightly to strongly down-regulated in RO (DPP IV: ↓ twofold, NEP: ↓ thirtyfold; tumor vs normal).