To elucidate the mechanism underlying the effects of GRB10 in the combination of ATO and APA in SCLC cells, we investigated the protein expression of VEGFR2, P-Akt, P-mTOR, P-GSK-3β, β-catenin and c-Myc in the sh-GRB10 cells. Here, KDR is linked to small cell lung carcinoma.