Expression of matrix metalloproteinase-9 in histological grades of oral squamous cell carcinoma: An immunohistochemical study

CONTEXT: Oral squamous cell carcinoma (OSCC) is characterized by a high degree of local invasiveness and metastasis to cervical lymph nodes and distant sites. Degradation of extracellular matrix (ECM) requires the concerted action of several extracellular enzymes, the most prominent of which are matrix metalloproteinases (MMPs). Proteolytic degradation of ECM components by (MMP-9) facilitates carcinoma cell invasion, enhances angiogenesis and tumor progression. OBJECTIVE: To assess and correlate the immunohistochemical expression of MMP-9 with clinicopathological parameters and histological grades of OSCC. SETTINGS AND DESIGN: Thirty histopathologically diagnosed cases of OSCC including 12 cases of well-differentiated squamous cell carcinoma, 12 cases of moderately differentiated squamous cell carcinoma and 6 cases of poorly differentiated squamous cell carcinoma were included in the study group. MATERIALS AND METHODS: The samples were subjected to staining using monoclonal antibodies against MMP-9 and visualized using the polymer-HRP detection system. Expression of MMP-9 was assessed in tumor epithelium/parenchyma and connective tissue stroma separately, and the mean of both was considered as average MMP-9 expression. STATISTICAL ANALYSIS: The parametric independent samples “t” test, one-way ANOVA test and Pearson's correlation test were used for the statistical analysis. RESULTS: Immunoexpression of MMP-9 increased with advancing stage and histological grade of OSCC with statistically significant results. CONCLUSION: MMP-9 plays an important role in invasion and metastasis and can serve as an independent prognostic marker.