Expression characteristics of astrocyte elevated gene-1 (AEG-1) in tongue carcinoma and its correlation with poor prognosis

Astrocyte elevated gene-1 (AEG-1) expression is increased in diverse human cancers and plays a vital role in tumorigenesis and progression. The aim of this study was to investigate the clinicopathologic features and prognostic significance of AEG-1 in squamous cell carcinoma of the tongue (TSCC). Immunohistochemistry (IHC) was performed to examine AEG-1 protein expression in paraffin-embedded tissues from 93 patients with TSCC. Real-time PCR and western blot analyses were employed to examine AEG-1 expression in 4 pairs of primary TSCC and adjacent non-cancerous tissues from the same patient. Immunohistochemical results revealed that the positive rate for AEG-1 in TSCC tissues (48.39%, 45/93) was higher than that in the normal tongue tissues (10.00%, 3/30) (P < 0.001). These results were further confirmed between TSCC tissues and matched adjacent non-cancerous tissues by Western blot and RT-PCR. Simultaneously, AEG-1 protein level was positively correlated with differentiation degree (P < 0.001), clinical stage (P < 0.001), T classification (P = 0.007) and N classification (P = 0.012). Furthermore, patients with higher AEG-1 expression had shorter overall survival time. Multivariate analysis (Cox regression) also suggested that AEG-1 expression was an independent prognostic indicator for TSCC (P = 0.043). Our results indicate that AEG-1 expression is closely associated with carcinogenesis and progression of TSCC, and may represent a novel and valuable predictor for prognostic evaluation of TSCC patients.