Abstract
Membrane type-matrix metalloproteinase (MT-MMP) has been recently cloned as an activator of MMP-2 (gelatinase A) . The expression of MT-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 MTMMP is a key step in cancer invasion and metastasis. The purpose of this study was to examine the expression of MT-MMP and its correlation with cancer invasion and metastasis in human oral squamous cell carcinoma (HOSCC) . Expression of MT1-MMP, MT3-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%), MT3-MMP in 18 cases (54.5%), and 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) . As the mode of invasion increased from grade 1 to grade 4 D, the ratio of positive cases of MT1-MMP, MT3-MMP, and MMP-2 tended to increase, and the majority of diffusely invasive carcinomas (grade 4C and 4D) co-expressed MT1-MMP and MMP-2 (8/9 cases) . Carcinomas with lymph node metastasis also showed a high frequency of expression of MT1-MMP, MT3-MMP, and MMP-2. These results suggested that MT1-and MT3-MMPs co-expressed with MMP-2 may play an important role in cancer invasion and metastasis of HOSCC.
