Expression Of Membrane Type-1 Matrix Metalloproteinase In Human Oral Squamous Cell Carcinomas

Membrane type1-matrix metalloproteinase (MT1-MMP) has been recently cloned as an activator of MMP-2 (gelatinase A). The expression of MT1-MMP in human lung and gastric carcinomas has been found to correlate well with the activation of MMP-2, suggesting that the MMP-2 activation by MT1-MMP is a key step in cancer invasion and metastasis. The aim of this study is to examine the expression of MT1-MMP and its correlation with cancer invasion and metastasis in human oral squamous cell carcinomas (HOSCC). Expression of MT1-MMP and MMP-2 was examined by immunohistochemistry in 33 cases of HOSCC in relation to mode of cancer invasion and presence/absence of lymph node metastasis. Expression of MT1-MMP in the carcinoma cells was detected in 18 cases (54.5%) and of MMP-2 in 15 cases (45.5%). MT1-MMP was co-localized in the carcinoma cells in almost all MMP-2 positive cases (14/15 cases). The majority of diffusely invasive carcinomas co-expressed MT1-MMP and MMP-2 (8/9 cases), while carcinomas with lymph node metastasis also showed a high frequency of co-expression of MT1-MMP and MMP-2 (10/15 cases). These results suggest that MT1-MMP co-localized with MMP-2 may play a critical role in cancer invasion and metastasis of HOSCC.