Acquired Resistance Mechanisms of Lung Adeno-carcinoma to Gef itinib

Background and Objective Lung cancer, which has been proved to have fastest increasing rate of morbidity and mortality,

Background and Objective Lung cancer, which has been proved to have fastest increasing rate of morbidity and mortality,appears to be one of the most dangerous malignant tumor that is threatening human being＇s health and lives. In the past half century, the incidence and mortality of lung cancer has been keeping on increasing in most countries and regions. Chemotherapy has been an important role in the treatment of patients with NSCLC for over 30 years. However, most of treatment outcomes for NSCLC patients are far from satisfaction. Overexpression of epidermal growth factor receptor （EGFR） and constant activation of the gene by some type of mutations were found in 60% of NSCLC. Abnormal expression and activation of EGFR generally indicate poor prognosis. EGFR signaling pathway contributes to a number of cancer related events such as proliferation, apoptosis, angiogenesis and metastasis. The target therapy aimed at blocking EGFR signaling pathway is attractive. Gefitinib （ZD1839, Iressa, AstraZeneca） which is a reversible EGFR tyrosine kinase inhibitor is the first target therapy drug approved for treatment of advanced NSCLC,