Prevalence of human papillomavirus in skin tumors from repair deficient xeroderma pigmentosum patients

Transcriptome sequencing demonstrates that human papillomavirus is not active in cutaneous squamous cell carcinoma

Beta-papillomavirus (β-HPV) DNA is present in some cutaneous squamous cell carcinomas (cuSCC), but no mechanism of carcinogenesis has been determined. We used ultra-high throughput sequencing of the cancer transcriptome to assess whether papillomavirus transcripts are present in these cancers. Sixty-seven cuSCC samples were assayed for β-HPV DNA by PCR, and viral loads were measured with type-specific qPCR. Thirty-one SCCs were selected for whole transcriptome sequencing. Transcriptome libraries were prepared in parallel from the HPV18 positive HeLa cervical cancer cell line and HPV16 positive primary cervical and periungual SCC. Thirty percent (20/67) of the tumors were positive for β-HPV DNA, but there was no difference in β-HPV viral load between tumor and normal tissue (p=0.310). Immunosuppression and age were significantly associated with higher viral load (p=0.016 for immunosuppression; p=0.0004 for age). Transcriptome sequencing failed to identify papillomavirus expression in any of the skin tumors. In contrast, HPV 16 and 18 mRNA transcripts were readily identified in primary cervical and periungual cancers and HeLa cells. These data demonstrate that papillomavirus mRNA expression is not a factor in the maintenance of cuSCC.

p16 expression in conventional and desmoplastic trichilemmomas

The expression of p16 in cutaneous neoplasms is upregulated in melanocytic neoplasms, ultraviolet radiation-induced neoplasms, such as actinic keratoses and squamous cell carcinomas, and in lesions related to human papillomavirus, such as Bowen's disease and bowenoid papulosis. In cervical dysplasia and tonsillar carcinoma, there is such a close relationship between p16 and human papillomavirus (HPV) to the extent that p16 immunostaining is used as a surrogate marker for the presence of HPV proteins. In this study we were interested in the expression pattern of p16 in trichilemmomas. Twenty-six conventional and 19 desmoplastic trichilemmomas were immunohistochemically stained for p16. p16 immunostaining was noted in the majority of conventional (80.8%) and desmoplastic trichilemmomas (73.7%). The staining pattern was both nuclear and cytoplasmic. The staining intensity was more pronounced in the desmoplastic variant. We describe for the first time p16 expression in trichilemmomas and discuss our findings in conjunction with p16 expression found in other cutaneous neoplasms. Additionally, the relationship of p16 to HPV infection is critically evaluated.