The successful development and use of mouse MCC tumor models revealed that transgenic expression of ATOH1, along with viral ST and/or LT in basal epithelial cells, gives rise to MCC-like tumors from the hair follicle, suggesting that ATOH1, an essential lineage factor for Merkel cell development (15), is critical for MCV-induced MCC (16). The gene discussed is ATOH1; the disease is Merkel cell skin cancer.