Prognostic factors and immunobiologic insights into Merkel cell carcinoma

Merkel cell carcinoma is an aggressive cutaneous neuroendocrine cancer, and although the current staging system takes into account several prognostic features, further study is needed to better determine whether other clinicopathologic features are also predictive of survival. The discovery of the Merkel cell polyomavirus with persistently expressed viral epitopes and an understanding of the various immune evasion mechanisms in Merkel cell carcinoma tumors provide an exciting and unique opportunity for the development of rational immune therapies to improve patient outcomes for this biologically unique, virus-associated cancer.