Recent advances in the understanding of the genetics, etiology, and treatment of Merkel cell carcinoma.

Merkel cell carcinoma (MCC) is a highly aggressive skin malignancy. The growing incidence and recognition of this cancer in elderly or immunosuppressed individuals suggests that it is becoming an increasing clinical challenge. MCC recently has been demonstrated to have a probable viral pathogenesis related to a novel member of the polyomavirus (termed Merkel cell polyomavirus [MCV]). The molecular pathogenesis of viral carcinogenesis is currently being worked out in MCC. Current diagnostic and therapeutic strategies are discussed, with an eye toward the future development of molecularly targeted treatments.