To identify that the BMSC‐EV‐derived let‐7i was involved in the occurrence and development of lung cancer by inhibiting the DCLK1/FXYD3 axis through KDM3A, BMSCs were transfected with mimic‐NC or let‐7i mimic and then BMSC‐EVs were extracted and added to lung cancer cells transfected with si‐FXYD3, respectively. The gene discussed is KDM3A; the disease is lung carcinoma.