EPCAM and cancer: Epithelial cSCCs (>70% EpCAM+ cancer cells), mixed cSCCs (10–70% EpCAM+ cancer cells), and mesenchymal cSCCs (<10% EpCAM+ cancer cells) were generated after engrafting full epithelial cancer cells from WD-SCCs, and EpCAM+ (including EpCAMhigh and EpCAMlow cells) and EpCAM− cancer cells from MD/PD-SCCs, respectively, into immunocompetent syngeneic mice (Supplementary Fig. 1a).