The Merkel Cell Polyomavirus: an oncogenic virus infecting humans

The Merkel cell polyomavirus has been named after a rare type of skin cancer, Merkel cell carcinoma, in which the virus was identified in 2008. It belongs to a family that includes well-known carcinogenic viruses in animals. Five years later, data are now available on Merkel cell polyomavirus structure, genomic organization, protein functions and replication cycle although there is still a need of in vitro and in vivo models. Despite the ubiquitous aspect of the MCPyV infection, the identification of several tumour specific viral markers supports that Merkel cell polyomavirus is indeed an etiologic agent of Merkel cell carcinoma. Moreover, whereas some mechanisms previously described with others polyomavirus have been confirmed, some new interactions between cellular and viral proteins have been identified that pave the way to the understanding of the molecular mechanisms underlying cellular transformation. Finally, in a clinical perspective, Merkel cell polyomavirus research brings potential tools for diagnosis, prognosis evaluation and new therapeutic approaches to manage Merkel cell carcinoma, a severe disease the frequency of which is increasing.