Expression of miR-221 in colon cancer correlates with prognosis

MicroRNAs are increasingly important in the study of cancer because of their ability to down regulate the expression of tumor suppressors and promote tumorigenesis. Here, miR-221, which is dysregulated in various tumors, was investigated for its expression in colon cancer tissues and its correlation with patient prognosis. Colon cancer tissue samples were obtained from 182 individuals who underwent surgical resection in our hospital from June 2008 to September 2009. Real-time PCR was used to detect the expression of miR-221 in these tissues. Patient survival was determined by telephone interview, and survival curves were plotted by using the Kaplan-Meier method and compared by the Log-rank test. Statistical methods also included X-2 test and Cox proportional hazard regression model. Differences in the expression of miR-221 by gender, pathology, and pathological staging were not statistically significant (P>0.05), but differences in the expression of miR-221 among age groups were statistically significant (P<0.05). A survival analysis indicated that high expression of miR-221 was closely associated with a shorter survival time (P<0.05). Further, later p-TNM (hazard ratio, HR=2.973, 95% confidence interval, CI: 1.329-6.519, P=0.003) and high expression of miR-211 (HR=2.394, 95% CI: 1.210-4.910, P=0.006) were identified as risk factors for colon cancer prognosis. Thus, high miRNA-221 expression might be a prognostic marker of colon cancer patients. The high expression of miRNA-221 was associated with poor prognosis of patients with colon cancer.