Merkel cell polyomavirus in the pathogenesis of non-melanoma skin cancer

Abstract

Merkel cell carcinoma (MCC) is a very aggressive neuroendocrine carcinoma of the skin. The recently identified Merkel cell polyomavirus (MCPyV) is present in the majority of MCCs. MCPyV clonally integrates in the tumor DNA and tumor-specific viral mutations are detected within the large T-antigen. To elucidate a possible role of MCPyV in the pathogenesis of other non-melanoma skin cancers (NMSC), i.e. squamous cell carcinoma, Bowen's disease and basal cell carcinoma we tested a group of these tumors in immunosuppressed and immunocompetent patients. In addition we tested MCPyV-positive tumors for viral mutations within the large T-antigen. MCPyV DNA was significantly more frequently detected in the NMSC of the immunosuppressed patients (p<0.001). No tumor specific mutations were found within the large T-antigen. The presence of the virus in tumor cells was confirmed by FISH analysis. Although MCPyV is present in the tumor cells of squamous cell carcinoma, Bowen's disease and basal cell skin carcinoma, further investigations into the role of MCPyV in the pathogenesis of these tumors is needed.