In addition, though this combination or single agent significantly caused the apoptosis of both KRAS mutant cancer cells and wild-type cells, it is observed that the two inhibitors’ combination obviously enhanced the ability of apoptosis induction in lung cancer cells harboring KRAS mutation, indicating the combination of RAF and STAT3 inhibitors is an effective therapy for treating lung cancer cells harboring KRAS mutations. The gene discussed is KRAS; the disease is lung cancer.