MMP9 and gastric cancer: The expression of ITGB6 in gastric cancer tissues was associated with matrix metalloproteinase 9 (MMP-9), and ITGB6 might participate in the invasiveness of gastric cancer as a downstream effector of vascular endothelial growth factor (VEGF), indicating that ITGB6 is a key molecule that involved in the invasiveness and metastatic potential of gastric cancer (14–17).