Compared with cells transfected with oe‐KDM3A, let‐7i in cells treated by oe‐KDM3A + EV‐inhibitor‐NC was notably increased; however, the KDM3A expression was significantly down‐regulated, whereas the proliferation, migration and invasion abilities of lung cancer cells were reduced. The gene discussed is KDM3A; the disease is lung carcinoma.