Prognostic significance of AEG-1 expression in colorectal carcinoma

Abstract

Astrocyte elevated gene-1 (AEG-1), as an HIV-1 or TNF-alpha-inducible transcript, is associated with various aspects of tumor malignancy. However, relatively little knowledge is available related to the role of AEG-1 in colorectal carcinoma. By immunohistochemical and western blot analysis, we investigated AEG-1 expression in normal mucosa, adenomas, and carcinomas of colorectum. By statistical analysis, we determined its relationship with clinicopathological parameters and overall survival in colorectal carcinoma. We found that AEG-1 expression levels were gradually elevated in normal tissues, low-grade adenoma, high-grade adenoma, and colorectal carcinoma, respectively. Though AEG-1 staining mainly emerged in the cytoplasm, we observed that nuclear staining of AEG-1 tends to become more common in lesions from patients with more advanced disease stages. Furthermore, there was a similar trend for Ki67 expression (as a proliferative index) from normal mucous to adenoma and carcinoma. Statistical analysis revealed that AEG-1 expression was markedly correlated with the UICC stage (P < 0.001), T classification (P = 0.002), N classification (P = 0.015), M classification (P = 0.010), Ki67 expression (P = 0.012), and histological differentiation (P = 0.037) in the colorectal cancer patients. Besides, those patients with high AEG-1 levels had shorter survival time (P < 0.001). High AEG-1 expression correlates with poor overall survival in the colorectal carcinoma patients. In addition, AEG-1 expression in colorectal carcinoma may be associated with tumor progression, indicating that AEG-1 may be a potential preventive and chemotherapeutic target in the patients.