Prognostic role of MMP-9 expression in head and neck carcinoma patients treated with radiotherapy or chemoradiotherapy

Abstract

The purpose of this study was to evaluate the prognostic significance of the expression of metalloproteinases (MMPs)-2 and -9 at a transcriptional level in patients with head and neck squamous cell carcinoma (HNSCC). Real-time polymerase chain reaction was used to determine mRNA expression levels of MMP-2 and MMP-9 in 105 consecutive patients with HNSCC treated with radiotherapy or chemoradiotherapy. Continuous values of mRNA expression levels were analyzed using a classification and regression tree (CART) method. Patients were grouped into two categories according to the results from CART analysis; high (n=71) and low (n=34) expression levels of MMP-9. MMP-2 expression was not included in the model. The 5-year adjusted survival rate was 92.9% for patients with low MMP-9 expression level and 61.0% for patients with a high expression level (P=0.006). Overexpression of MMP-9 was associated with a decrease in local control of the disease. In a multivariate analysis, MMP-9 expression was the only variable that was associated with adjusted survival. Considering patients with a low MMP-9 expression level as the reference group, patients with a high MMP-9 expression level had a 6.1 times higher risk of death from HNSCC (CI 95%: 1.4-26.4). We found a significant relationship between the transcription of MMP-9 and adjusted survival in HNSCC patients treated with radiotherapy or chemoradiotherapy. These results suggest that MMP-9 transcription may serve as a marker of treatment response to radiotherapy or chemo-radiotherapy in patients with HNSCC.