Reply to: High-grade urothelial carcinoma in a kidney transplant recipient after JC virus nephropathy: The first evidence of JC virus as a potential oncovirus in bladder cancer.

We read with interest the recent article by Querido et al regarding the JC virus related urothelial carcinoma after kidney transplantation (1). In Taiwan and China, the upper urinary tract urothelial carcinoma (UT-UC) is a relatively prevalent disease and the risk of post kidney transplantation (KT) urothelial carcinoma increases up to 31-fold compared with general population (2,3). Positive JC virus DNA was reported up to 90.1% using polymerase chain reaction (PCR) analysis while immunohistochemical staining also revealed 30% large T antigen expression(4) in a Taiwan UT-UC cohort. The post KT immunocompromised status and early oncogenic viral protein related to JC virus reactivation might play an important role of carcinogenesis.