MATRIX METALLOPROTEINASE-2 CONCENTRATIONS IN SQUAMOUS CELL CARCINOMA OF THE HEAD AND NECK AND ITS CLINICAL SIGNIFICANCE

Tumor cells degrade extracellular matrix components (ECM) to invade surrounding tissues. Cancer cells are known to produce various ECM-degrading enzymes including matrix metalloproteinases (MMPs), serine proteinases and cathepsins. Type IV collagen is one of the major components of the basement membrane, and it composes the structural scaffold of these specialized sheets of the ECM. The enzymatic degradation of type IV collagen is initiated by MMPs, in particular MMP-2 (a 72 kDa type IV collagenase) and MMP-9 (a 92 kDa type IV collagenase) which play a key role in cancer invasion and metastasis. In this study, we investigated MMP-2 concentrations and the activity of type IV collagenase in cancer tissue homogenate in 21 cases with head and neck carcinomas and 6 cases with normal mucosa. MMP-2 concentrations did not differ between normal mucosa and tumor tissue without lymphnode metastases. Type IV collagenase activity in normal mucosa was below the detection limit. MMP-2 concentrations had no relation to tumor size, however MMP-2 concentrations in tumor tissue with lymphnode metastases were higher than that in cases without lymphnode metastasis (35.8 +/- 20.5, 20.0 +/- 9.7 ng/mg protein, respectively). However, there was no correlation between MMP-2 concentrations and type IV activity in tumor tissues. These results suggest that MMP-2 plays an important role in tumor invasion and metastasis, so MMP-2 could be a useful biological tumor marker for metastasis and prognosis.