SMAD2 and gastric cancer: The results showed that the transient overexpression of SMAD2 enhanced the proliferation, migration, and invasion of GC cells (SGC-7901 and HGC-27 cells) compared with the blank control; of note, the combination of the transient transfection of SMAD2 and miR-4256 inhibitor could partly eliminate the promoting effect on the malignant biological behavior caused by SMAD2 overexpression.