Downregulation of chromatin remodeling factor CHD5 is associated with a poor prognosis in human glioma

Chromodomain helicase DNA-binding protein 5 (CHD5), a member of the CHD family, is involved in key cellular processes including chromatin remodeling, cell cycle regulation, and cellular adhesion. Recent studies have demonstrated that CHD5 is the product of a novel tumor suppressor gene and is implicated in certain tumor types. However, the clinicopathological significance of CHD5 expression in human malignant gliomas remains unclear. To address this problem, CHD5 expression in human gliomas and non-neoplastic brain tissues was measured using real-time quantitative polymerase chain reaction (RT-PCR) assay, Western blot, and immunohistochemistry. The association of CHD5 immunostaining with clinicopathological factors or prognosis of glioma patients was statistically analyzed. Genetic and protein expression of CHD5 were downregulated in glioma tissues compared to corresponding non-neoplastic brain tissues (both p<0.001). Additionally, decreased expression of CHD5 in glioma was significantly associated with pathological grade (p=0.007); high pathological grade was associated with low CHD5 expression. Loss of CHD5 protein expression was also significantly correlated with a low Karnofsky performance scale score (p=0.01). Moreover, overall survival of patients with low CHD5 protein expression was dramatically shorter than those of patients with high CHD5 protein expression (p=0.003). Multivariate Cox regression analysis indicated that CHD5 expression was an independent prognostic factor for patients with gliomas (p=0.01). In conclusion, these data offer convincing evidence for the first time that CHD5 might act as a tumor suppressor in glioma, may act as a regulator of aggressive development, and is a candidate prognostic marker for this malignancy.