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.