IGF1 and cancer: In the hypoxic TME of ESCC, a distinct fibroblast subpopulation termed hypoxia-induced senescent cancer-associated fibroblasts (hsCAFs) has been identified; these cells secrete insulin-like growth factor 1 (IGF1) to promote tumor stemness and chemoresistance, underscoring hsCAFs as promising therapeutic targets (Ou et al., 2025).