Increased Nicotinamide Phosphoribosyltransferase and Cystathionine-β-Synthase in Renal Oncocytomas, Renal Urothelial Carcinoma, and Renal Clear Cell Carcinoma

Abstract

Background: Renal oncocytomas (ROs), and clear cell (RCC) and urothelial carcinomas (UC), are common renal neoplasms. Nicotinamide phosphoribosyltransferase (Nampt) catalyzes the rate-limiting step of NAD⁺ synthesis and its expression is increased in several tumors. Nampt concomitantly regulates hydrogen sulfide (H₂S)-synthesizing enzyme levels, including cystathionine-β-synthase (CBS).

Materials and methods: We used tissue microarrays to examine Nampt and the H₂S-synthesizing enzyme CBS protein levels in benign kidney, RCC, UC and ROs.

Results: Compared to benign kidney, all three neoplasms showed increased Nampt and CBS protein levels, with the levels increasing in RCC at higher Fuhrman grades.

Conclusion: H₂S is known to ameliorate chronic renal failure but, as yet, no role for H₂S in renal neoplasia has been demonstrated. Here, we showed, for the first time, that Nampt, CBS and, likely, H₂S likely play a role in malignant and benign neoplastic renal disease.

Keywords: Fuhrman grade; Renal cancer; cystathionine-β-synthase; nicotinamide phosphoribosyltransferase.