Though we have confirmed the effects of miR-449a and KDM3A on lung cancer, and identified the targeting relation between miR-449a and KDM3A, as well as between KDM3A and HIF-1α, the internal mechanism of miR-449a/KDM3A/HIF-1α axis is not yet clear. The gene discussed is HIF1A; the disease is lung carcinoma.