TO THE EDITOR

Epidermal melanocytes (MCs) are spe-cialized melanin-producing cells (Slo-minski et al., 2004; Yamaguchi et al., 2007; Thomas and Erickson, 2008; Park et al., 2009) that synthesize melanin within the melanosome (Slominski et al., 2004) and protect individuals from harmful UV rays (Slominski et al., 2004; Yamaguchi et al., 2007; Thomas and Erickson, 2008; Park et al., 2009). Defects in or a lack of MCs can lead to melanoma, pigment disorders, and auditory defects. MC proliferation and differentiation in skin is tightly linked to hair regeneration cycles. MCs in vertebrates are derived from neural crest (Thomas and Erickson, 2008). In hair follicles, melanoblasts are segre-gated into hair matrix MCs (for hair pigmentation) and melanocyte stem cells (MCSCs). The discovery of MCSCs and induced pluripotent (iPS) cells provides important resources to eluci-date mechanisms underlying melano-genesis and pathogenesis of MC-relate