ALDH1A1 and pachyonychia congenita: Immunofluorescence (IF) staining of several notable CSC makers (YAP1, EpCAM, ALDH1, and SOX9) in three cell lines (Fig. 2B) and its donor PC cells (Supplemental Fig. 2) showed expression of YAP1, EpCAM, ALDH1, and SOX9 was heterogenous and varied in three PC cell lines with highest of GA0518 cells which are similar to their donor PC cells (Fig. 2B & Supplemental Fig. 2).