Merkel Cell Polyomavirus: The New Kid on the Block
Jason Diaz, Margo MacDonald and Jianxin You
from: DNA Tumour Viruses: Virology, Pathogenesis and Vaccines (Edited by: Sally Roberts). Caister Academic Press, U.K. (2018) Pages: 201-214.
Merkel cell polyomavirus (MCPyV or MCV) is the first polyomavirus clearly shown to be associated with human cancer. Nearly all healthy adults asymptomatically shed MCPyV from their skin. In elderly and immunosuppressed individuals, infection can lead to a highly lethal form of skin cancer, Merkel cell carcinoma (MCC). Excessive exposure to sunlight and ultraviolet (UV) radiation, immune suppression, and advanced age are the most important risk factors for MCPyV-associated MCC. The incidence of MCC has tripled over the past two decades, and the concern for MCC grows as the aging population with prolonged sun exposure increases. With the high prevalence of MCPyV infection and an increasing amount of MCC diagnoses, there is a need to better understand the biology of MCPyV and its oncogenic potential. This chapter summarizes recent discoveries in MCPyV molecular virology, host cellular tropism, cell culture infection and animal models, and the unique genetic features of MCPyV that make it the only polyomavirus discovered to date that is associated with a human cancer. MCPyV is more likely to induce MCC in immunocompromised patients, thus providing an excellent probe for examining the role of the host immune system in controlling virus-induced oncogenesis. The interplay between MCPyV infection and host immune response and how disruption of this virus-host interaction may contribute to MCC pathogenesis is also reviewed. Together, our current knowledge provides a platform for future mechanistic studies to fully elucidate the MCPyV infectious life cycle and the mechanisms by which MCPyV infection contributes to MCC pathogenesis read more ...