ADRB2 and gastric neoplasm: We noticed that the overexpression of MMP-7 emerged at the region where β2-AR was expressed highly and the level of MMP-7 and β2-AR is the highest in the metastatic locus of gastric cancer, suggesting a direct role of β2-AR-mediated MMP-7 expression in the invasion and metastasis of gastric cancer, and also implying an important effect of neuroendocrine "macroenvironment" on the gastric tumor microenvironment.