Molecular Mechanisms of Human Papillomavirus Induced Skin Carcinogenesis.

Infection of the cutaneous skin with human papillomaviruses (HPV) of genus betapapillomavirus (ßHPV) is associated with the development of premalignant actinic keratoses and squamous cell carcinoma. Due to the higher viral loads of ßHPVs in actinic keratoses than in cancerous lesions, it is currently discussed that these viruses play a carcinogenic role in cancer initiation. In vitro assays performed to characterize the cell transforming activities of high-risk HPV types of genus alphapapillomavirus have markedly contributed to the present knowledge on their oncogenic functions. However, these assays failed to detect oncogenic functions of ßHPV early proteins. They were not suitable for investigations aiming to study the interactive role of ßHPV positive epidermis with mesenchymal cells and the extracellular matrix. This review focuses on ßHPV gene functions with special focus on oncogenic mechanisms that may be relevant for skin cancer development.