MYCL and Merkel cell skin cancer: Because MCV T antigens alone are not sufficient to transform normal human fibroblasts (Cheng et al., 2017), MCC-specific oncogenic factors that are amplified in MCC such as L-Myc, may also play important roles in MCV-induced MCC carcinogenesis (Paulson et al., 2009; Cheng et al., 2017).