Merkel cell polyomavirus is more frequently present in North American than Australian Merkel cell carcinoma tumors,” The

Merkel cell carcinoma (MCC) is an increasingly common neuroendocrine cancer of the skin. MCC is an aggressive malignancy that is a significant cause of non-melanoma skin cancer deaths. Although the genetics of MCC are poorly characterized, it is well established that MCC is associated with advanced age and ultraviolet-light exposure. MCC is also linked to immune suppression; 8 % of MCC patients are chronically immunosuppressed, which is a 16-fold over-representation(Heath et al., 2008). In particular, MCC is linked to T cell dysfunction associated with malignant, infectious and iatrogenic causes(Heath et al., 2008),(Engels et al., 2002),(Miller and Rabkin, 1999). Recently, Feng et al. described a novel polyomavirus that is associated with Merkel cell carcinoma(Feng et al., 2008). This virus, named Merkel cell polyomavirus (MCPyV), was present in 8 of 10 MCC tumors as compared to 1 of 15 normal skin controls. Several clues suggest a possible functional role for this virus in cancer. MCPyV shares key features with the SV40 polyomavirus, an oncogenic virus in animals, such as the predicted ability of a viral protein to bind and inactivate the tumor suppressor Rb. Furthermore, MCPyV DNA was reported to be monoclonally integrated into six of the tumors, which implies that vira