title: BK virus-associated urinary bladder carcinoma in transplant recipients: report of 2 cases, review of the literature, and proposed pathogenetic model.
abstract: Despite strong experimental evidence, BK polyomavirus involvement in human cancers has been controversial. We report 2 cases of kidney ± pancreas transplant recipients with evidence of BK polyomavirus reactivation, who developed aggressive urinary bladder urothelial carcinomas with adenocarcinomatous and/or micropapillary differentiation. Diffuse strong nuclear positivity for viral T antigen, p53, Ki-67, and p16 was observed in both malignancies. The BK polyomavirus role in promoting urothelial neoplasia in transplant recipients may be partly indirect, based on the demonstration by polymerase chain reaction in both tumors of BK polyomavirus with intact open reading frames and close phylogenetic clustering with known replication-competent strains, and viral capsid protein VP1 messenger RNA and intranuclear virions by electron microscopy in 1 tumor. No unique cancer-associated mutations were found, but some viral T antigen mutations were potentially associated with increased rate of viral replication and risk for "rare" carcinogenic events. The BK polyomavirus-induced profound effects on cell activation, cell cycle shift to proliferation, and apoptosis inhibition, in the context of marked immunosuppression, constitute a potentially ideal background for malignant transformation. The long time lapse between transplantation and tumor manifestation, 7 and 11 years, respectively, further supports the concept of multistep carcinogenesis cascade and long-term risk for these patients. We propose a model of changes ranging from viral reactivation to dysplasia to invasive carcinoma. Clinical vigilance is warranted for early diagnosis of BK polyomavirus-related urothelial malignancies in transplant recipients.
authors: Department of Pathology, University of Maryland Medical Center, Baltimore, MD 21201, USA. balexiev@umm.edu
authors: Borislav A
authors: BA
authors: Alexiev
authors: Parmjeet
authors: P
authors: Randhawa
authors: Eduardo
authors: E
authors: Vazquez Martul
authors: Gang
authors: G
authors: Zeng
authors: Chunqing
authors: C
authors: Luo
authors: Emilio
authors: E
authors: Ramos
authors: Cinthia B
authors: CB
authors: Drachenberg
authors: John C
authors: JC
authors: Papadimitriou
mesh_terms: D000230:Adenocarcinoma / Q000209:etiology* / Q000821:virology; D000328:Adult; D000957:Antigens, Viral, Tumor / Q000235:genetics; D001739:BK Virus / Q000235:genetics* / Q000276:immunology; D005260:Female; D006801:Humans; D007165:Immunosuppression Therapy / Q000009:adverse effects; D016030:Kidney Transplantation / Q000009:adverse effects*; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D027601:Polyomavirus Infections / Q000150:complications*; D014412:Tumor Virus Infections / Q000150:complications*; D001749:Urinary Bladder Neoplasms / Q000209:etiology* / Q000821:virology; D014775:Virus Activation; D014779:Virus Replication
chemical_list: D000957:Antigens, Viral, Tumor