Background: Matrix metalloproteinases (MMPs) have been implicated in the invasion and metastasis of head and neck squamous cell carcinoma (HNSCC). However, a detailed analysis of MMPs and tissue inhibitors of MMPs (TIMPs) in relation to the biological behavior of HNSCC has yet to be performed in clinical material.
Objectives: To study a comprehensive profile of MMPs and their 2 main inhibitors in HNSCC tissue samples and to correlate the patterns of expression with clinicopathological characteristics, invasion, and metastasis.
Design: This study included 54 consecutive patients with primary HNSCC, 27 of which showed lymph node metastasis. Expression of MMP-1, MMP-2, MMP-3, MMP-7, MMP-9, MMP-10, MMP-11, MMP-13, MMP-14, TIMP-1, and TIMP-2 was simultaneously analyzed in tissue homogenates using semiquantitative reverse transcription-polymerase chain reaction assay. Where feasible, levels of protein and enzyme activity were confirmed by Western blot, enzyme-linked immunosorbent assay, and substrate zymography. Conventional clinicopathological features, including mode of tumor invasion, were also examined.
Results: Significantly higher MMP-1, MMP-2, MMP-3, MMP-7, MMP-9, MMP-10, MMP-11, MMP-13, and TIMP-1 levels were found in tumors vs specimens of matched normal mucosa. No difference in the distribution of MMPs and TIMPs in relation to age, sex, tumor site, or histological grade was observed. A significant correlation was demonstrated between levels of MMP-1, MMP-9, and TIMP-1 and advanced T stage and between MMP-9 expression and an infiltrative pattern of growth. Enhanced expression of MMP-9 was strongly correlated (P<.001) and levels of MMP-2, MMP-7, and MMP-11 were weakly correlated (P =.03-.05) with lymph node involvement.
Conclusions: Overexpression of multiple MMPs and TIMPs is characteristic of HNSCC, and analysis of specific MMPs, MMP-9 in particular, might be useful for evaluating the malignant potential in individual HNSCC.