On the other hand, when lung cancer cells were added with EV‐let‐7i‐inhibitor, the expression of KDM3A was up‐regulated, thus promoting lung cancer cell proliferation, migration and invasion, suggesting that the BMSC‐EV‐derived let‐7i was a suppressor of KDM3A in lung cancer cells and an inhibitor of the proliferation, migration and invasion of lung cancer cells. The gene discussed is KDM3A; the disease is lung carcinoma.