Published in:
01-07-2010 | Original Paper
Expression level of Bmi-1 oncoprotein is associated with progression and prognosis in colon cancer
Published in: Journal of Cancer Research and Clinical Oncology | Issue 7/2010
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Purpose
To investigate the clinicopathologic significance and predictive value of Bmi-1 expression in patients with colon cancer.
Methods
Bmi-1 expression was assessed by immunohistochemistry, PCR, and western blotting in specimens from 203 patients and by immunohistochemistry in 66 specimens of lymph node metastasis (LNM).
Results
Positive staining of Bmi-1 occurred in 7.9% (16/203), 66.5% (135/203), and 86.4% (57/66) of specimens from normal tissue, colon cancer, and LNM, respectively. Staining was significantly correlated with clinical stage, depth of invasion, nodal involvement, distant metastasis, and Ki67 level. Bmi-1 was upregulated at the transcriptional and translational levels. Patients with Bmi-1-positive localized tumors had a much lower 5-year disease-free survival (relative risk 2.919, P < 0.0001) and overall survival (relative risk 5.056, P < 0.0001). Bmi-1 immunoreactivity emerged as an independent prognostic factor in the multivariate analysis.
Conclusions
We have shown that expression of Bmi-1 was elevated in colon cancer and might serve as an independent prognostic marker.