Expression of matrix metalloproteinase-7 and fas ligand: Their apoptosis-inducing effect on gastric cancer cells

Objective: To investigate the expression of matrix metalloproteinase-7 (MMP-7) and Fas ligand (FasL) in gastric cancer and explore their role in progression of gastric cancer. Methods: Formalin-fixed paraffin and embedded tissues of primary gastric cancer and adjacent non-tumor mucosa from 113 cases were evaluated for MMP-7, FasL and Capase-3 expression by streptavidin-peroxidase (S-P) immunohistochemistry. The expression of the first two proteins in cancer cells of primary foci was compared with clinicopathological parameters of tumors. We also observed the correlation of MMP-7 and FasL expression with Caspase-3 expression in cancer cells of primary foci. Results: MMP-7 positive immunostaining was less frequently detected in adjacent epithelial cells than in cancer cells of primary foci of gastric cancer ( P <0.05, 29.2% vs 69.0%), and so was FasL ( P <0.05, 34.5% vs 54.0%). MMP-7 expression was associated with tumor size, Borrmann’s classification, invasive depth, metastasis and TNM staging ( P <0.05), but not with growth pattern, Lauren’s classification, or histological classification ( P >0.05). FasL expression was correlated with tumor size, invasive depth, metastasis, Lauren’s classification, histological classification ( P <0.05), while not with Borrmann’s classification, TNM staging or growth pattern ( P >0.05). Cancer cells of primary foci expressed less Caspase-3 than their adjacent epithelial cells ( P <0.05,32.7% vs 50.4%). There was an obvious correlation between FasL, MMP-7 and Caspase-3 expression in cancer cells of primary foci ( P <0.05). Co-expression of MMP-7 and FasL paralleled with Caspase-3 expression in cancer cells of primary foci ( P <0.05). Conclusion: MMP-7 and FasL expression was up-regulated in gastric carcinogenesis and was principally involved in progression of gastric cancer. FasL expression could reflect the differentiation of gastric cancer cells and underlie the molecular mechanisms of different pathways of gastric tumorigenesis. Co-expression of MMP-7 and FasL could have apoptosis-inducing effect on gastric cancer cells.