Expression of matrix metalloproteinases and tissue inhibitor of metalloproteinases in head and neck squamous cell carcinoma.

Matrix metalloproteinases (MMPs) are a family of proteolytic enzymes implicated in the invasion and metastasis of many cancers. In situ hybridization techniques were used to reveal sites of expression of collagenase (MMP-1), gelatinase 72 kd (MMP-2), gelatinase 92 kd (MMP-9), and tissue inhibitor of metalloproteinase-1 (TIMP-1) in head and neck carcinomas (N = 21). Both TIMP-1 and gelatinase 72 kd were expressed in nearly all tumors, whereas the expression of collagenase and gelatinase 92 kd showed variability. Tumor-associated expression of MMPs was strongest in stromal cells near advancing margins. No differences in expression levels were detected between primary and metastatic sites. This paper reviews the literature and discusses the significance and possible implications of MMPs in head and neck squamous cell carcinoma.