Abstract
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. © 2005 Wiley‐Liss, Inc.