CASP9 and cancer: Further studies showed that glabridin down-regulated the levels of phosphorylated epidermal growth factor receptor (P-EGFR) and phosphorylated protein kinase B (P-AKT) and promoted the expression of cysteine-aspartic acid protease 3 (caspase-3), cysteine-aspartic acid protease 8 (caspase-8), and cysteine-aspartic acid protease 9 (caspase-9), indicating that glabridin exerts its anti-cancer effects by regulating the activation of the EGFR signaling cascade.