Clinicopathologic and prognostic significance of MMP-7 (matrilysin) expression in human rectal cancer

Objective: There is increasing evidence to indicate that MMP-7 plays a more important role in tumor progression than other MMPs. The aim of this study was to detect MMP-7 expression in human rectal cancer and normal rectal tissue and to determine whether it is correlated with invasion and metastasis of human rectal cancer. Methods: Eighty-six paired samples of rectal cancer and distant normal rectal tissue obtained from 100 inpatients were allocated into two groups (cancer group and control group). MMP-7 mRNA was detected by relative quantitative real-time RT-PCR and MMP-7 protein was examined by immunohistochemical staining and computerized image analysis. Results: MMP-7 mRNA expression in cancer group was higher than that in control group (P = 0.006), the expression ratios of 31 samples (37.35%) were < 1 and 52 (62.65%) were > 1. The mRNA expression level was correlated with Dukes Staging, histological differentiation grade and CEA level. The MMP-7 protein expression was in accordance with mRNA expression level. The positive degree of immunohistochemical staining in cancer group (1.82 +/- 0.03) was different from that in control group (1.17 +/- 0.13, P = 0.002). Moreover, in cancer group the positive staining degree in high-level mRNA cancers (2.04 +/- 0.18, n = 52) was higher than that in low-level mRNA ones (1.58 +/- 0.23, n = 31, P = 0.008). Conclusions: Our results suggest that MMP-7 plays an important role in the progression of human rectal cancer. MMP-7 may be selected as a clinical diagnosis and prognosis index in rectal cancer.