KRT19 and lung cancer: The expression pattern was validated at multiple levels: (i) with high folds epithelial genes expression (KRT18, KRT19, EPCAM, ICAM1 and CDH1) by quantitative PCR (Fig 5C), (ii) GSEA of hallmark apical junction and apical surface gene‐sets enrichment with SP gene‐sets activation pattern in lung cancer patients (Figs 5D and EV2H–J), (iii) enhanced expression of cell adhesion (EPCAM) and tight junction (ZO‐1) proteins at the cytoplasmic membrane region (Figs 5E and EV2K), and (iv) increased epithelial transcription factors GRHL1 and OVOL2 upon SP treatment (Fig 5F).