Compared with cells treated by si‐FXYD3 + EV‐mimic‐NC, let‐7i and FXYD3 expression in cells treated by si‐FXYD3 + EV‐let‐7i mimic were significantly increased, the expressions of KDM3A and DCLK1 were noticeably down‐regulated, whereas the proliferation and invasion of lung cancer cells were inhibited remarkably, whereas the number of apoptotic cells was significantly increased (Figure 6A‐E). The gene discussed is KDM3A; the disease is lung cancer.