Wang et al. Journal of Experimental & Clinical Cancer Research 2012, 31:44 http://www.jeccr.com/content/31/1/44 R E S E A R C H Open Access Elevated expression of chloride intracellular channel 1 is correlated with poor prognosis in human gliomas Liang Wang1†, Shiming He1†, Yanyang TU2†, Peigang Ji1, Jianhai Zong1, Jingyu Zhang1, Fuqiang Feng1, Jipei Zhao1, Yongsheng Zhang2* and Guodong Gao1* Abstract Background: Chloride intracellular channel 1 (CLIC1) is expressed ubiquitously in human tissues and is involved in the regulation of cell cycle, cell proliferation and differentiation. Recent studies have shown that CLIC1 is highly expressed in several human malignant tumors. However, its roles in human gliomas are still unclear. The aim of this study was to investigate the clinicopathological significance and prognostic value of CLIC1 expression in human gliomas. Methods: CLIC1 expression in human gliomas and nonneoplastic brain tissues was measured by real-time quantitative RT-PCR assay and immunohistochemistry. Its association with clinicopathological factors or prognosis in patients with gliomas was statistically analyzed. Results: The expression of CLIC1 at both mRNA and protein levels was significantly increased in high-grade (Grade III~IV) glioma tissues compared with that in low-grade (Grade I~II) and nonneoplastic brain tissues, and was up-regulated with ascending tumor World Health Organization (WHO) grades. The elevated expression of CLIC1 protein was also significantly correlated with low Karnofsky performance score (KPS) (P=0.008). Moreover, both univariate and multivariate analysis shown that high CLIC1 expression was significantly associated with poor prognosis in patients with gliomas (P<0.001 and P=0.01, respectively). In particular, the elevated CLIC1 expression also correlated with shorter overall survival in different glioma subgroups stratified according to the WHO grading. Conclusions: Our data provide the first evidence that CLIC1 expression might play an important role in the regulation of aggressiveness in human gliomas. The elevated expression of CLIC1 might represent a valuable prognostic marker for this disease. Keywords: Chloride intracellular channel 1, Glioma, Real-time quantitative RT-PCR assay, Immunohistochemistry, Prognosis Introduction Human gliomas represent the most common primary brain tumors in both children and adults. According to histo- pathological and clinical criteria established by the World Health Organization (WHO), this dismal disease can be classified as well-differentiated low grade astrocytomas * Correspondence: zhangys_td@163.com; gguodong1@163.com †Equal contributors 1Department of neurosurgery, Tangdu hospital, Fourth Military Medical University of PLA, No.569, Xinsi Road, Baqiao District, Xi’an City 710038, China 2Department of experimental surgery, Tangdu hospital, Fourth Military Medical University of PLA, No.569, Xinsi Road, Baqiao District, Xi’an City 710038, China [World Health Organization (WHO) grade I~II], anaplastic astrocytomas (WHO grade III) and glioblastoma multi- forme (GBM, WHO grade IV) [1]. Despite recent thera- peutic advances, the survival of patient with glioma is still poor. The median overall survival of patients with malig- nant gliomas is no more than one year and local recurrence occurs in more than 90% of patients [2]. Recent studies have indicated that patients’ age, Karnofsky performance status (KPS) score, histologic grade, and tumor necrosis are important prognostic factors for gliomas [3]. However, the prognosis of both high- and low-grade tumors remains het- erogeneous. The median survival time of patients with © 2012 Wang et al.; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.