detected the expression of let-7i, lysine demethylase 3A (KDM3A), bicorticoid kinase 1 (DCLK1) and ion transport regulator 3 (FXYD3) containing FXYD domain in lung cancer tissues, then determined the regulatory relationship among them, and observed the effects of them on lung cancer cells. The gene discussed is FXYD3; the disease is lung cancer.