Clinical implications of AEG-1 in liver metastasis of colorectal cancer

The aim of the study was to investigate the role of AEG-1 in colorectal cancer and the relationship between AEG-1 protein expression and pathological characteristics and prognosis in colorectal cancer. The AEG-1 mRNA and protein expression level between the tumor cells from the cases with liver metastasis and those from the ones without live metastasis were detected by RT-PCR and immunohistochemistry staining. The relationship between AEG-1 and clinicopathological parameters of colorectal cancer was determined. AEG-1 expressed positively in 218 (41.92%) of the 520 cases examined. It showed that both mRNA and protein level AEG-1 were over-expressed in the cases with liver metastasis compared with those without liver metastasis (P = 0.01). After immunohistochemistry analysis, the expression of AEG-1 protein was related to age, Duke's stage and distant metastasis (P = 0.001, 0.001 and 0.016, respectively). After survival analysis, the cases with highly expressed AEG-1 protein attained a significantly poorer postoperative disease-specific survival than those with none/low-expressed AEG-1 protein (P = 0.001). In the Cox regression test, histological grade, Duke's stage and AEG-1 were detected as the independent prognostic factors (P = 0.035, 0.001 and 0.010, respectively). AEG-1 protein may be a potential new early liver metastasis biomarker of colorectal cancer.