Wang et al. Journal of Experimental & Clinical Cancer Research 2012, 31:44 http://www.jeccr.com/content/31/1/44 Page 2 of 7 high-grade gliomas range from 5 to 59 months and some patients with low-grade tumors also present poor outcome [4]. Similar with other human solid tumors, the predomin- ant features of gliomas are extensive local tumor invasion and metastasis, in which multiple molecular events are involved. Focusing on these genetic background and mo- lecular pathogenic processes is necessary to identify novel diagnostic and prognostic markers for improving the clin- ical outcome of patients with gliomas. In mammals, the chloride intracellular channel (CLIC) gene family has six members, including CLIC1, CLIC2, CLIC3, CLIC4, CLIC5, and CLIC6 [5]. This family is defined by a conserved, approximately 230 amino acid core sequence which comprises the C-termini of all known CLICs. CLIC1 is a newly discovered member of the CLIC family [6]. In 1997, it was originally cloned from a human monocytic cell line activated by the phorbol ester, phorbol 12-myristate 13 acetate [7]. CLIC1 is expressed ubiquitously in human tissues and is usually localized in the cytoplasm and nucleoplasm with a soluble form. It has been demonstrated to be involved in the regu- lation of cell cycle, cell proliferation and differentiation [8]. In the G2/M phase, CLIC1 is detected on the plasma membranes of cells, and the inhibition of CLIC1 function prolongs the mean time of the cell cycle in cell culture [9]. Recent studies have found that CLIC1 is over-expressed in malignant tumors, such as hepatocellular carcinoma [10], gallbladder carcinoma [11], gastric carcinoma [12], and colorectal cancer [13,14]. CLIC1 has been considered as a sensor and an effector during oxidative stress, which may lead cells through all the phases of the cell cycle [15]. Thus, CLIC1 is hyperactivated in cancer cells which are in a highly proliferative state, and plays important roles in tumor invasion and metastasis. In central nervous system, several lines of evidence support that CLIC1 plays a fundamental role in activated microglia and is involved in the pathophysiology of sev- eral neurodegenerative diseases [16]. Additionally, Kang et al. [17] found that small cell populations of GBM2 cancer stem cells (CSCs) were resistant to chemothera- peutic agent BCNU and highly expressed CLIC1. They further demonstrated that CLIC1 was involved in the re- sistance of BCNU-resistant CSCs. However, the clinico- pathological significance and prognostic value of CLIC1 in clinical glioma specimens are still unclear. To address this problem, CLIC1 expression in human gliomas and nonneoplastic brain tissues were measured by immuno- histochemistry. The association of CLIC1 immunostain- ing with clinicopathological factors or prognosis of glioma patients was statistically analyzed. Materials and methods Patients and tissue samples This study was approved by the Research Ethics Com- mittee of Tangdu Hospital, Fourth Military Medical Uni- versity, P. R. China. Written informed consent was obtained from all of the patients. All specimens were handled and made anonymous according to the ethical and legal standards. A total of 128 formalin-fixed, paraffin-embedded spe- cimens of gliomas resected between 2000 and 2010 were retrieved from the archives of the Pathology Department of Tangdu Hospital, Fourth Military Medical University, P. R. China. All the slides were re-evaluated according to Table 1 Clinicopathological features of 128 patients with gliomas Features Case No. Mean age (year) Gender Male Female KPS >80 <80 Surgery Gross total resection Partial resection Biopsy Adjuvant treatment Radiotherapy Chemotherapy Radiotherapy and Chemotherapy combination WHO I 18 38.6 12 6 15 3 18 0 0 0 0 0 WHO II 14 45.9 6 8 11 3 14 0 0 0 1 0 WHO III 38 43.1 25 13 9 29 28 9 1 30 0 5 WHO IV 58 44.2 33 25 15 43 38 15 5 12 6 28