EGFR and lung cancer: Simultaneous treatment of H1650 and H1975 cells with honokiol and erlotinib caused significantly higher growth inhibitory activities and more potent modulatory effects on phospho-EGFR (H1975 cells), total EGFR, total and phopho-Akt, total and phospho-ERK and PARP cleavage, compared to treatment with honokiol or erlotinib alone, indicating the promise of combinatory treatment with erlotinib and honokiol to improve the clinical response of patients with erlotinib-resistant lung cancer.