Prognostic significance of matrix metalloproteinase-7 (MMP-7) expression at the invasive front in gastric carcinoma.

To evaluate the clinicopathological significance of matrix metalloproteinase-7 (MMP-7) expression in gastric carcinoma, we investigated immunohistochemically MMP-7 expression in 214 gastric carcinomas, and examined its relations with the clinicopathologic parameters including patient prognosis. MMP-7 expressed predominantly in cancer cells, and MMP-7-positive tumor cells were preferentially found in deeply invading nests, especially at the invasive front. The mean MMP-7 labeling index (LI) at the invasive front was significantly higher in tumors invading or penetrating the muscularis propria and in stages II - IV than within the submucosal layer and in stage I, respectively (P < 0.001). Statistical analysis revealed that MMP-7 LI at the invasive front was related to lymph node metastasis, vascular invasion, and lymphatic permeation, when all 214 cases were examined as one group (P < 0.05 for all), and the cases with high MMP-7 expression at the invasive front showed significantly more unfavorable prognosis as compared with that of low MMP-7 expression tumors (P < 0.01). Multivariate analysis revealed that TNM stage and MMP-7 expression status at the invasive front were independent prognostic factors (P = 0.0017, relative risk (RR) = 3.12; P = 0.0019, RR = 2.67, respectively). Our findings indicated that expression of MMP-7 at the invasive front is closely associated with local invasiveness, and might be a reliable prognostic marker for patients with gastric carcinoma.