Prevalence and Abundance of Human Cutaneous Polyomaviruses in the Healthy Population and Patients with Keratinocyte Carcinomas

Abstract

Background Human polyomavirus (HPyV) is a part of the healthy, commensal skin virome. However, certain HPyV species with skin tropism are linked with symptomatic inflammatory and neoplastic skin conditions in elderly and immunosuppressed populations. Accurate characterisation of cutaneous HPyVs is essential for downstream research and analyses. Methods To build an in-house complementary molecular technique-based system to detect the three most common cutaneous HPyVs: Merkel cell polyomavirus (MCPyV), human polyomavirus 6 (HPyV6) and 7 (HPyV7), we tested the performance of previously reported HPyV primers and probes with quantitative and qualitative polymerase chain reaction (qPCR and PCR) methods on human skin tissue samples and skin swabs. Results The qPCR method reliably detected and quantified MCPyV, HPyV6 and HPyV7 in fresh frozen skin tissues and swabs. The efficiency of the qPCR was 88.4%, 83.9% and 71.7% for MCPyV, HPyV6 and HPyV7, respectively. The detection limit of cutaneous HPyVs was around 70-140 copies/qPCR reaction. There was a correlation between the band intensity of the class PCR product on the agarose gel after electrophoresis and the qPCR result. Conclusion The in-house qPCR system could detect the presence of cutaneous HPyVs qualitatively and quantitatively.

Background The association between cutaneous human polyomavirus (HPyV) and keratinocyte carcinoma, including cutaneous squamous cell carcinoma (cSCC) and basal cell carcinoma (BCC), is controversial. Critical information is lacking regarding the prevalence and abundance of cutaneous commensal HPyVs in keratinocyte carcinoma patients. Methods We applied an in-house cutaneous HPyV detection system to characterise the presence of Merkel cell polyomavirus (MCPyV), human polyomavirus 6 (HPyV6) and 7 (HPyV7) on the non-lesional skin tissue. The relationship between viral detection rates, viral loads and cancer status was examined in 100 non-lesional surgical cone skin samples from keratinocyte carcinoma patients. MCPyV status was compared between the patients and the healthy population. Results A majority of the patients harboured all three commensal HPyVs, and cSCC patients had a significantly elevated frequency of MCPyV compared with BCC patients (p = 0.049). The mean MCPyV viral load was higher in cSCC patients, though the statistical significance was not met (p = 0.15). MCPyV was significantly more abundant than the other two cutaneous HPyVs in the surgical cones of cSCC patients (p = 0.003 and 0.001) but not in BCC patients. Conclusion The project demonstrated that MCPyV might be a potential biomarker for cSCC risk assessment.