Increased expression of MMP9 is correlated with poor prognosis of nasopharyngeal carcinoma

Zhen Liu,Bin Wu,Zhixiong Yang,Weiren Luo,Kaitai Yao,Xin Li,Huiling Yang,Lixia Li,Weiyi Fang

doi:10.1186/1471-2407-10-270

Abstract

IntroductionThe aim of the present study was to analyze the expression of matrix metalloproteinase 9 (MMP9) in nasopharyngeal carcinoma (NPC) and its correlation with clinicopathologic features, including the survival of patients with NPC.MethodsUsing real-time PCR, we detected the mRNA expression of MMP9 in normal nasopharyngeal tissues and nasopharyngeal carcinoma (NPC) tissues. Using immunohistochemistry analysis, we analyzed MMP9 protein expression in clinicopathologically characterized 164 NPC cases (116 male and 48 female) with age ranging from 17 to 80 years (median = 48.4 years) and 32 normal nasopharyngeal tissues. Cases with greater than or equal to 6 and less than 6 of the score value of cytoplasmic MMP9 immunostaining were regarded as high expression and low expression, respectively. The relationship between the expression levels of MMP9 and clinical features was analyzed.ResultsThe expression level of MMP9 mRNA was markedly greater in NPC tissues than that in the nasopharyngeal tissues. Immunohistochemical analysis revealed that the protein expression of MMP9 detected in NPC tissues was higher than that in the nasopharyngeal tissues (P = 0.004). In addition, high levels of MMP9 protein were positively correlated with the status of lymph node metastasis (N classification) (P = 0.002) and clinical stage (P < 0.001) of NPC patients. Patients with higher MMP9 expression had a significantly shorter overall survival time than did patients with low MMP9 expression. Multivariate analysis suggested that the level of MMP9 expression was an independent prognostic indicator (P = 0.008) for the survival of patients with NPC.ConclusionHigh level of MMP9 expression is a potential unfavorable prognostic factor for patients with NPC.

Highlights

The aim of the present study was to analyze the expression of matrix metalloproteinase 9 (MMP9) in nasopharyngeal carcinoma (NPC) and its correlation with clinicopathologic features, including the survival of patients with NPC
In order to clarify the role of MMP9 in the pathogenesis of NPC, in the present study we investigated the correlation of MMP9 protein expression with clinicopathologic features, including the survival of patients
We found that the mRNA and protein expression levels of MMP9 were higher in NPC tissues than those in non-cancerous nasopharyngeal tissues

Summary

Introduction

The aim of the present study was to analyze the expression of matrix metalloproteinase 9 (MMP9) in nasopharyngeal carcinoma (NPC) and its correlation with clinicopathologic features, including the survival of patients with NPC. Nasopharyngeal carcinoma (NPC) is one of the most common malignant diseases in the Chinese and other south-east Asians. Most NPC patients tend to present a more advanced stage of disease when first diagnosed due to its deep location and vague symptoms. MMP9, a member of the matrix metalloproteinases (MMPs), plays a critical role in breakdown of extracellular matrix in normal physiological processes, such as embryonic development, reproduction, and tissue remodeling, as well as in disease processes, such as tumor metastasis[3]. MMP9 is secreted from cells and, once activated, is thought to degrade collagen in the extracellular matrix, which promotes the metastasis of tumor cells [4]

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