Low expression of microRNA-126 is associated with poor prognosis in colorectal cancer.

MicroRNA-126 (miR-126) has been reported to be a tumor suppressor that targets CXCR4 in colorectal cancer (CRC) cells. This study investigated whether miR-126 has any prognostic impact in patients with CRC. MiR-126 and CXCR4 mRNA expression in 92 pairs of CRC and adjacent nontumorous tissues was examined using quantitative real-time PCR, and CXCR4 protein expression was assessed by immunohistochemistry (IHC) and Western blotting. The correlation between miR-126 and CXCR4 protein expression and clinicopathological features and overall survival rate was determined. MiR-126 was downregulated in CRC tissues that expressed high levels of CXCR4 mRNA. IHC and Western blotting detected high expression of CXCR4 protein in CRC tissues. An inverse correlation was observed between miR-126 and CXCR4 protein expression in CRC tissues. Moreover, low miR-126 and high CXCR4 protein expression was associated with distant metastasis, clinical TNM stage, and poor survival. Multivariate analysis indicated that miR-126 was an independent prognostic factor for overall survival, suggesting its clinical significance as a prognostic predictor in CRC patients.