Prognostic value of interleukin-8 and MMP-9 in nasopharyngeal carcinoma

Nasopharyngeal carcinoma (NPC) is one of the leading causes of cancer related death in China. One of the reasons is the absence of tumor specific prognostic markers. The aim of this study was to examine the prognostic values of interleukin-8 (IL-8) and matrix metalloproteinase-9 (MMP-9) in NPC patients. A total of 99 consecutive NPC patients and 40 healthy controls were recruited for this study. Serum levels of IL-8 and MMP-9 were evaluated in NPC patients who were followed up for 5 years. The serum levels of IL-8 and MMP-9 in NPC patients were significantly higher than those in healthy controls (IL-8 26.3 [2.9-68.0] ng/ml vs. 20.3 [2.3-38.6] ng/ml, P < 0.001; MMP-9 23.5 [3.6-52.1] ng/ml vs. 17.3 [2.6-36.9] ng/ml, P = 0.002), respectively. The serum levels of IL-8 and MMP-9 were positively correlated with the N classification (IL-8, P = 0.041, and MMP-9, P < 0.001, respectively) and clinical stage (IL-8, P = 0.022, and MMP-9, P < 0.001, respectively) in NPC patients. Analysis using the Kaplan-Meier method indicated that patients with high levels of IL-8 or MMP-9 had significantly shorter overall survival (OS) (IL-8, P = 0.012; MMP-9, P < 0.001) and disease-free survival (DFS) (IL-8, P = 0.021; MMP-9, P = 0.003) time than those with low levels of MMP-9 or IL-8. Univariate and multivariate analysis revealed elevated MMP-9 level was an independent predictor of shorter OS and DFS. Both MMP-9 and IL-8 are involved in NPC progression. MMP-9 in serum may be the clinically useful indicator for prognostic evaluation in NPC patients.