MMP9 and gastric cancer: Constitutive activation of STAT3 in gastric epithelial cells promotes cellular proliferation, invasion, and angiogenesis, and inhibits apoptosis by activating various associated target genes including cyclin D1, VEGF-1, Bcl-xL, survivin and MMP-9 [15, 16]., A recent meta-analysis showed that increased p-STAT3 expression in gastric cancer tissue is significantly associated with undifferentiated type, lymph node metastasis and poor prognosis [17].