Serum matrix metalloproteinase-9 in head and neck squamous cell carcinoma is a prognostic marker.

The aim of this study was to determine whether serum matrix metalloproteinase-9 (MMP-9) could predict cause-specific and relapse-free survival in patients with squamous cell carcinoma of head and neck. Furthermore, this study was designed to investigate whether there is an association between MMP-9 immunohistochemical staining and serum MMP-9 levels. Pretreatment serum levels of MMP-9 were quantitatively measured by ELISA assay in 67 patients presenting with a primary head and neck squamous cell carcinoma. The results were compared with the corresponding immunohistochemical staining results, clinical data and the patients' outcome. The follow-up time for all of the patients was at least 5 years. There was a statistically significant correlation between circulating MMP-9 and MMP-9 immunohistochemical staining in the corresponding tumors (p = 0.028). The cause-specific and relapse-free survival rates were clearly lower among patients with high MMP-9 serum levels (> 73 ng/ml). The 5-year cause-specific survival-rate was 40% in a patient group with high serum MMP-9, and 69% for patients with a low MMP-9 level (p = 0.027). In the same follow-up period, the cumulative relapse-free survival rate was 36% in patients presenting with a high serum MMP-9 and 66% in those with a low MMP-9 level. No correlation was found between MMP-9 serum levels and the traditional clinical or histopathologic factors. The results suggest for the first time that pretreatment serum MMP-9 level could serve as a prognostic factor in head and neck squamous cell carcinoma.