ABSTRACT
<p><b>OBJECTIVE</b>To investigate the expression of B cell specific MLV integration site-1 (Bmi-1) in colorectal cancer (CRC) and its correlation to the clinicopathological features and prognosis of CRC.</p><p><b>METHODS</b>Sixty CRC, 30 adenomas and 20 normal colorectal mucosal tissues were collected to detect the expression of Bmi-1 protein using immunohistochemistry, and the results were analyzed in comparison with the clinicopathological features and survival rate of patients.</p><p><b>RESULTS</b>The positivity rate of Bmi-1 expression in CRC tissue was 51.7%. In CRC, the rate of Bmi-1 overexpression was 25.0%, significantly higher than that in the adenomas and normal colorectal mucosal tissues (6.67% and 0%, respectively, P<0.05). The overexpression of Bmi-1 protein in CRC was obviously associated with distant metastasis and the TNM stage (P<0.05), but not with gender, age, tumor size, tumor site, histological type, differentiation degree and lymph node metastasis (P>0.05). But logistic regression analysis showed that Bmi-1 protein overexpression in CRC was associated only with distant metastasis (P<0.01,OR>1); Kaplan-Meier survival analysis showed that the survival rate of the patients with high Bmi-1 expression was significantly lower than that in patients with low expression (P<0.05).</p><p><b>CONCLUSION</b>The overexpression of Bmi-1 protein was significantly correlated to the tumorigenesis, metastasis and prognosis of CRC, and may serve as an indicator for evaluating the prognosis of CRC.</p>