Enhancement of apoptosis induction by the combination of EGFR siRNA plus afatinib or cetuximab. Experiments were performed as mentioned in Figure 10. (A: afatinib; B: cetuximab). *P < 0.05 and **P < 0.01 compared to controls with siRNA transfection alone. "black triangle" P < 0.05 and "double black triangles" P < 0.01 compared to agents plus control siRNA.