KRT1 and Bowen disease of the skin: Cells from donor sample SCC IV, a SCC arisen from Bowen’s disease (Table S2), mainly clustered in KC2, KC4, and KC5 that showed reduced expression of KRT1, KRT10. KC2 and KC5 also displayed expression of KRT16 and KRT19, respectively, which has been previously described for this SCC subtype52 (Figs. 2A and S2C).