TWIST1 and melanoma: First, we selected the top 20 genes with consecutive upregulation during differentiation (Figure 6A), allowing us to discover PRAME (preferentially expressed antigen in melanoma) (Epping et al., 2005) and TWIST1 (twist family bHLH transcription factor 1) (Qin et al., 2012), both of which exhibited robust and rapid upregulation at the early stage of MSC differentiation from hPSCs under the above optimal or sub-optimal circumstances (Figures 6B and S6A).