We then addressed whether cancer cell-derived EVs promoted NSCLC cell growth by regulating the Smad9/BMP4 pathway and thus, CCK-8 proliferation assay (Fig. 7e, Additional file 4: Figure S4E) and colony formation assay (Fig. 7f, Additional file 4: Figure S4F) were performed. The gene discussed is SMAD9; the disease is cancer.