SPP1 and keloid: IPA revealed upregulation of GLI1 target secretory cytokines involved in tissue fibrosis, osteopontin (OPN, encoded by SPP1, secreted phosphoprotein 1)49, fibroblast growth factor 1 (FGF1)50, and insulin-like growth factor binding protein-7 (IGFBP7)51, in keloid-derived stem-like cells; these cytokines regulated signals in keloid-derived fibroblasts (Fig. 4a–c and Supplementary Fig. 7a–c).