Immunoexpression of matrix metalloproteinase‐2 and matrix metalloproteinase‐9 in the metastasis of squamous cell carcinoma of the human tongue

BACKGROUND: Squamous cell carcinoma of the tongue has frequent lymph node metastases and poor prognosis. Matrix metalloproteinase-2 (MMP-2) and matrix metalloproteinase-9 (MMP-9) are reported to degrade basement membrane,facilitating invasion and metastasis. This study determined the expression of MMP-2/MMP-9 in primary tongue cancer with or without cervical metastases and analysed the significance of such expression in relation to the presence or absence of metastases. METHODS: Expressions of MMP-2⁄MMP-9 were detected by immunohistochemistry in 10 specimens of normal oral mucosa, 20 lymph node-negative tongue cancers, 41 lymph node-positive tongue cancers and their metastasized tumours in cervical lymph nodes. RESULTS: MMP-2⁄MMP-9 expression was seldom found in normal epithelium. In lymph node-negative tongue cancer, 45% and 40% of these primary tumours were positively stained for MMP-2⁄MMP-9, respectively. Importantly, in lymph node-positive tongue cancer, 71% and 79% of these primary tumours were positive for MMP-2⁄MMP-9, respectively. Overexpression of MMP-2⁄MMP-9 was present in the metastatic lymph nodes. CONCLUSIONS: Our results imply that MMP-2 and/or MMP-9 play an important role in invasion and metastasis in tongue cancer, and that analysis of MMP expression and/or activity in primary tumours may have a predictive value for the actual or potential presence of cervical metastases.