Circ-LDLRAD3 was an oncogenic factor in non-small cell lung cancer through miR-491-5P / mitogen-activated protein kinase kinase kinase 3 (MAP3K3) and miR-137 / lysine (K)-specific demethylase 1A (SLC1A5) pathways. The gene discussed is MAP2K3; the disease is small cell lung carcinoma.