BDNF and lung carcinoma: To verify the roles of BDNF in mediating the effect of TNFR2 KO in lung tumor growth and SCZ, and expression of BDNF and TrkB, we injected BDNF (by intravenous injection, 160 μg/kg every 4 days for 28 days including the first day of xenograft) in our A549 lung cancer cells xenograft mice model.