We found that siRNA-mediated depletion of EGFR, HER2, or HER3 resulted in inhibition of cell proliferation and induction of apoptosis accompanied by inhibition of AKT and ERK signalling pathways in lung cancer cells with MET amplification, although these effects were less pronounced that were those of MET depletion. The gene discussed is ERBB2; the disease is lung carcinoma.