MedicalResearch.com Interview with: Prof. Dr. med. Sigrun Smola Institute of Virology, Saarland University Homburg/Saar, Germany MedicalResearch.com: What is the background for this study? Response: Non-melanoma skin cancer (NMSC), the most common cancer in humans, is caused by UV-irradiation. The potential co-factor role of cutaneous genus beta-human papillomaviruses (beta-HPV) in skin carcinogenesis, particularly in immunosuppressed patients, has become a major field of interest. However, the underlying mechanisms were unclear. The skin has natural mechanisms providing protection against UV-induced damage. One important factor suppressing UV-induced skin carcinogenesis is the transcription factor C/EBPα belonging to the CCAAT/enhancer binding protein family. C/EBPα can induce cellular differentiation and is regarded as a tumor suppressor in various tissues. When C/EBPα expression is blocked in these tissues, tumorigenesis is enhanced. Another important factor is the microRNA-203. It has been shown to control “stemness” in normal skin by suppressing a factor called p63. In many tumors miR-203 expression is shut off releasing this “brake”. In our study we demonstrate that cutaneous beta-HPV interferes with both protective factors providing an explanation how cutaneous beta-HPV enhances the susceptibility to UV-induced carcinogenesis. Moreover, we provide evidence that these viruses regulate miR-203 via C/EBPα. We have investigated this mechanism in Epidermodysplasia verruciformis (EV) patients that serve as a human model disease for studying the biology of genus beta-HPVs. They are highly susceptible to persistent genus beta-HPV infection, such as HPV8, and have an increased risk to develop non-melanoma skin cancer at sun-exposed sites. (more…)