Merkel Cell Carcinoma: Update on Pathogenesis and Therapy

Merkel cell carcinoma is a cutaneous cancer with a high propensity to metastasize, which mostly affects elderly patients. The increased incidence among the immunosuppressed led to the discovery of an infectious causal agent: the Merkel cell polyomavirus. This was the first step of considerable progress in understanding this cancer: virus-induced oncogenesis, host immune responses, immune evasion mechanisms. Although surgery and radiation therapy remain the mainstay of therapy, such progress allowed emerging strategies such as immunotherapy among patients with advanced stages. However, their efficiency remains incomplete and there is yet no targeted therapy with demonstrated efficacy in these patients: innovative therapeutic strategies are still crucial.