In contrast, transient SMAD2 knockdown by siRNA attenuated proliferation, migration, and invasion in GC cells (SGC-7901 and HGC-27 cells) compared with the blank control, while the combination of transient SMAD2 knockdown and transient miR-4256 overexpression markedly reversed the inhibitory effect of silencing SMAD2 on GC cell proliferation (Fig. 10A), migration and invasion (Fig. 10B). This evidence concerns the gene SMAD2 and gastric cancer.