In A549 cells, the combination of STE029 and Gefitinib could downregulate p-Akt (P < 0.001) and upregulate cleaved caspase-8 and cleaved caspase-9 (P < 0.001); (5)In vivo, the combination of STE029 and Gefitinib effectively inhibited tumor development and progression compared to STE029 alone or Gefitinib alone, with significant difference (P < 0.05) in PC9 and PC9/BB4 xenografted tumor. The gene discussed is CASP9; the disease is neoplasm.