Objective: To investigate the expression and distribution of matrix metalloproteinase 9(MMP 9) in gastric mucosa with different morphology and to elucidate its association with tumor progression.

• 目的 :检测基质金属蛋白酶（ matrix metalloproteinase 9,MMP－ 9）在各类人胃粘膜中的表达频率，并观察其分布特点及其与胃癌发生和发展的关系。