Overexpression of AEG-1 in renal cell carcinoma and its correlation with tumor nuclear grade and progression

The study was aimed at detecting the expression of a newly found oncogene, astrocyte elevated gene-1 (AEG-1), in renal cell carcinoma (RCC) and its correlation with histopathologic features and the survival of patients. Real-time reverse transcription-PCR and Western blot showed markedly higher expression of AEG-1 in 8 cases of RCC tissue compared with the paired normal tissue from the same patient. The expression level of AEG-1 was also increased in four RCC cell lines in contrast with normal tubular epithelial human kidney cells 2 (HK-2) at both mRNA and protein levels. Furthermore, immunohistochemistry analysis showed highly expressed AEG-1 in 96 of 102(94.1%) cases of paraffin-embedded archival RCC tissue. Statistical analysis showed a significant correlation of AEG-1 expression with tumor grade (P <0.001), clinical staging (P = 0.003), T classification (P = 0.003) as well as metastasis classification (P=0.032). The means for survival time of low AEG-1 expression group was 76.98m while high AEG-lexpression group was 60.94m. Our results suggest that AEG-1 protein is overexpressed in RCC and plays an important role in tumor differentiation and progression. High AEG-1 expression is closely associated with poor prognosis.