STAT3 and cancer: Immunohistochemical (IHC) analysis with the anti-K116Ac antibody (whose specificity was previously validated; Figure S7a) showed that FRA1 was mostly identified in the nucleus of cancer cells while its K116-acetylated form mainly localized to the cytoplasm (Fig. 6b; Figure S7b), thus indicating that phosphorylated STAT3 can activate FRA1 both by transcriptional upregulation and deacetylation leading to increased NANOG expression levels.