MicroRNAs as Promising Biomarkers for Tumor-staging: Evaluation of MiR21 MiR155 MiR29a and MiR92a in Predicting Tumor Stage of Rectal Cancer

Objective: In this study, tumor-stage predictive abilities of miR21, miR155, miR29a and miR92a were evaluated in rectal cancer (RC). Methods: Expression of miR21, miR155, miR29a and miR92a was detected and quantitated in tumor tissue and in adjacent normal tissue from 40 patients by TaqMan MicroRNA assay. Results: Significant overexpression of miR21, miR155, miR29a and miR92a was observed in RC tissues. While high expression of miR21, miR155 and miR29a in N1-2 and C-D stages presented a potential correlation with N and Duke stages, partial correlation analysis suggested that only miR155 rather than miR21 and miR29a played a greater influencing role. Receiver operating characteristics (ROC) curve analysis showed that miR155 could discriminate N0 from N1-2 with 85.0% sensitivity and 85.0% specificity, N2 from N0-1 with 90.0% sensitivity and 96.7% specificity, and C-D stage from A-B stage with 81.0% sensitivity and 84.2% specificity. Conclusions: Increase in expression of miR155 might represent a novel predictor for RC N and Dukes staging.