DCLK1 and lung cancer: 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.