Transient receptor potential vanilloid type 1 (TRPV1) expression changes from normal urothelium to transitional cell carcinoma of human bladder

OBJECTIVE: To investigate possible changes in the expression of the transient receptor potential vanilloid type 1 (TRPV1) from normal urothelium to transitional cell carcinoma (TCC) of human bladder. METHODS: Specimens from normal bladder (n=13, mean age 62 yrs), superficial TCC (n=16, mean age 62,4 yrs) and muscle invasive bladder cancer (n=12, mean age 67 yrs), were obtained by multiple cold cup and full-thickness biopsy during open surgery. All the specimens were processed for H&E staining, immunohistochemistry and Western Blot analysis. RESULTS: In controls, the urothelium showed a labelling whose intensity was higher in the superficial cells than in the basal and club-shaped ones. In the superficial TCC, the urothelium showed a reduced labelling intensity. In the muscle invasive TCC, a very light labelling was occasionally detected in scattered superficial cells and no labelling was present in the basal cells and in those that had invaded the muscle. In controls, Western Blot analysis recognized two thick, intensely stained bands, with a molecular weight of approximately 100 and 95 kDa. In all superficial TCC there were two bands similar to control ones and in the muscle invasive two very thin, lightly stained bands. No band was detected in the patients staged as pT4. CONCLUSION: These data demonstrated a progressive loss of TRPV1 expression in the urothelium as TCC stage increased and cell differentiation was lower. Future studies will establish the importance of this loss for TCC differentiation and progression.