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.

Kidney transplant (KT) recipients have an increased risk for urothelial carcinoma. A role for JC virus (JCV) in human cancers is not yet proved but there is an increasingly reported association between BK virus (BKV) nephropathy and renourinary neoplasms. We report a KT recipient who developed a high-grade urothelial carcinoma 5 years after a diagnosis of JCV nephropathy and 9 years after kidney transplantation. Neoplastic tissue was positive for JCV DNA by real-time polymerase chain reaction (PCR). Immunochemical staining showed strong positivity for cell cycle markers (p16, p53, and Ki67) and for early viral protein JCV large T antigen (JCV LTag; using a broad polyomavirus antibody); however, late viral protein (VP1) stained negative. In contrast, in non-neoplastic urothelium, JCV DNA and all immunochemical markers were negative. These facts suggest that malignancy was induced by JCV. To the best of our knowledge, this is the first report of urothelial high-grade carcinoma associated with JCV nephropathy in a KT recipient.