Research

Over-expression of eukaryotic translation initiation factor 4 gamma 1 correlates with tumor progression and poor prognosis in nasopharyngeal carcinoma

Luxia Tu^1,3* , Zhen Liu^1* , Xiufang He² , Ying He⁴ , Huiling Yang⁵ , Qingping Jiang¹ , Siming Xie¹ , Guanghui Xiao¹ , Xin Li¹ , Kaitai Yao¹ and Weiyi Fang¹

¹  Cancer Research Institute, key lab for transcriptomics and proteomics of human fatal diseases supported by ministry of education and Guangdong Province, Southern Medical University, 510515, Guangdong Province, PR China

²  Department of Otorhinolaryngology, People's hospital of Zhongshan City, 528403, Guangdong Province, PR China

³  Department of Otorhinolaryngology, Nanfang hospital of Southern Medical University, 510515, Guangdong Province, PR China

⁴  Department of Pathology of the first affiliated hospital, Nanchang University, Jiangxi Province, PR China, 330006

⁵  Institute of Clinical Medicine, First Affiliated Hospital of University of South China, Hengyang City, 421001, Hunan Province, PR China

author email corresponding author email* Contributed equally

Molecular Cancer 2010, 9:78doi:10.1186/1476-4598-9-78

Published:	16 April 2010

Abstract

Background

The aim of the present study was to analyze the expression of eukaryotic translation initiation factor 4 gamma 1 (EIF4G1) in nasopharyngeal carcinoma (NPC) and its correlation with clinicopathologic features, including patients' survival time.

Methods

Using real-time PCR, we detected the expression of EIF4G1 in normal nasopharyngeal tissues, immortalized nasopharyngeal epithelial cell lines NP69, NPC tissues and cell lines. EIF4G1 protein expression in NPC tissues was examined using immunohistochemistry. Survival analysis was performed using Kaplan-Meier method. The effect of EIF4G1 on cell invasion and tumorigenesis were investigated.

Results

The expression levels of EIF4G1 mRNA were significantly greater in NPC tissues and cell lines than those in the normal nasopharyngeal tissues and NP69 cells (P < 0.001). Immunohistochemical analysis revealed that the expression of EIF4G1 protein was higher in NPC tissues than that in the nasopharyngeal tissues (P < 0.001). In addition, the levels of EIF4G1 protein in tumors were positively correlated with tumor T classification (P = 0.039), lymph node involvement (N classification, P = 0.008), and the clinical stages (P = 0.003) of NPC patients. Patients with higher EIF4G1 expression had shorter overall survival time (P = 0.019). Multivariate analysis showed that EIF4G1 expression was an independent prognostic indicator for the overall survival of NPC patients. Using shRNA to knock down the expression of EIF4G1 not only markedly inhibited cell cycle progression, proliferation, migration, invasion, and colony formation, but also dramatically suppressed in vivo xenograft tumor growth.

Conclusion

Our data suggest that EIF4G1 can serve as a biomarker for the prognosis of NPC patients.