BK virus and cancer in Uganda

BK Polyomavirus: Clinical Aspects, Immune Regulation, and Emerging Therapies

BK polyomavirus (BKV) causes frequent infections during childhood and establishes persistent infections within renal tubular cells and the uroepithelium, with minimal clinical implications. However, reactivation of BKV in immunocompromised individuals following renal or hematopoietic stem cell transplantation may cause serious complications, including BKV-associated nephropathy (BKVAN), ureteric stenosis, or hemorrhagic cystitis. Implementation of more potent immunosuppression and increased posttransplant surveillance has resulted in a higher incidence of BKVAN. Antiviral immunity plays a crucial role in controlling BKV replication, and our increasing knowledge about host-virus interactions has led to the development of improved diagnostic tools and clinical management strategies. Currently, there are no effective antiviral agents for BKV infection, and the mainstay of managing reactivation is reduction of immunosuppression. Development of immune-based therapies to combat BKV may provide new and exciting opportunities for the successful treatment of BKV-associated complications.

Polyomavirus BK and prostate cancer: an unworthy scientific effort?

The Polyomavirus BK (BKV) has been proposed to be one of the possible co-factors in the genesis of prostate cancer (PCa) but, so far, the only convincing suggestion is the hypothesis of a “hit and run” carcinogenic mechanism induced by the virus at early stages of this disease. To support this hypothesis we conducted an updated systematic review on previous studies regarding the association between BKV and PCa, in order to interpret the contrasting results and to explore whether there might be a significant virus-disease link. This updated analysis provides evidence for a significant link between BKV expression and PCa development, particularly between the BKV infection and the cancer risk. Forthcoming scientific efforts that take cue from this study might overcome the atavistic and fruitless debate regarding the BKV-PCa association.

Absence of Simian virus 40, BK, and JC polyomavirus DNA in squamous cell carcinoma limited to the oral cavity

BACKGROUND

Head and neck squamous cell carcinomas (SCCs) are among the most aggressive types of cancer. The Simian virus 40 (SV40), which is a polyomavirus known for its oncogenic potential, was found as a contaminant of oral vaccines and has been related to human pleomorphic adenoma in the parotid gland. The aim of this study was to evaluate the presence of SV40 and 2 human polyomaviruses-BK virus (BKV) and JC virus (JCV)-in a large sample of SCCs of the oral cavity.

METHODS

Quantitative real-time polymerase chain reaction (PCR) was used to evaluate virus load.

RESULTS

Overall, the prevalence of SV40, BKV, and JCV in oral SCC was negligible. Matched-pair case-control analysis indicated that prevalence among the controls did not significantly differ with respect to analyzed cases.

CONCLUSION

The results did not indicate a major role for SV40, BKV, and JCV in the etiology of oral SCC.

[Urologic aspects of Polyomavirus infection]

JC virus (JCV) and BK virus (BKV) are human Polyomaviruses of the papovavirus family, which also includes a simian vacuolating virus 40 (SV40). Human Polyomaviruses were first isolated in 1971 from the brain (JCV) and urine (BKV) of two different patients. Human Polyomaviruses have a limited and specific tissue tropism infecting the renal tubular cells, the urothelium, the B cells and the brain cells. The virus infects the majority of the human population with seroconversion occurring during adolescence. The detection of the virus may be cytological, pathological, virological or immunological. Following a typically subclinical primary infection, Polyomavirus establishes a life-long persistent infection, especially in the urinary tract. BKV is known to reactivate and cause severe disease in immunosuppressed patients. The presence of Polyomavirus outside conditions of immunosuppression raises the question of its meaning and its therapeutic management. Given the ubiquitous nature of the virus and its strong association with cancer in animal models, they may play an etiological role in human malignancies. Here, we describe the biology of human Polyomaviruses, review their non-malignant and malignant potentials, and discuss the therapeutic aspect.

BK virus and human cancer: innocent until proven guilty

BK virus (BKV) is a polyomavirus that ubiquitously infects the human population. Following a typically subclinical primary infection, BKV establishes a life-long persistent infection in the kidney and urinary tract. BKV is known to reactivate and cause severe disease in immunosuppressed patients, particularly renal and bone marrow transplant patients. Infection of BKV in rodent animal models or cells in culture often results in tumor formation or transformation, respectively. When co-expressed with activated oncogenes, BKV large tumor antigen drives the transformation of primary human cells. An etiological role of BKV in human cancer, however, remains controversial. Multiple reports have demonstrated conflicting results in regards to the presence of BKV sequences and/or proteins in various tumor types. This review compiles the most recent findings of BKV detection in a number of human cancers. Due to the lack of conclusive causality data from these studies, there does not appear to be a definitive association between BKV and human cancers.

Antibody levels against BK virus and prostate, kidney and bladder cancers in the EPIC-Oxford cohort

In a case-control study nested within the EPIC-Oxford cohort, there were no statistically significant differences in the prevalence or titre of antibodies against BK virus measured in plasma taken prior to diagnosis between cases with cancer of the prostate (n=31), kidney (n=5) or bladder (n=9) and controls (n=45).