The following questions will be discussed: (1) whether CIB2 is essential for lung cancer growth and gefitinib resistance; (2) to investigate whether CIB2 regulates ZEB1 expression to induce gefitinib resistance; (3) to verify whether the aberrant expression of CIB2 is regulated by transcription factor FOSL1 and the role and mechanism of FOSL1/CIB2/ZEB1 pathway in lung cancer development and resistance to gefitinib. The gene discussed is ZEB1; the disease is lung cancer.