High expression of microRNA-126 relates to favorable prognosis for colon cancer patients

miR-126 has been identified both as a tumor suppressor and an oncogene in different types of cancer. The aim of this study was to investigate the prognostic impact of miR-126-expression in colon cancer patients. Tumor tissue from 452 patients operated for stage I–III colon cancer was retrospectively collected and tissue microarrays were constructed. miR-126 expression was evaluated by in situ hybridization and analyzed using digital pathology. To isolate the compartment specific contribution of miR-126, tumor and adjacent tumor stroma were considered separately. In univariate analyses, high expression of miR-126 in tumor and stroma was related to increased disease-specific survival (p < 0.001 and p = 0.005, respectively). In multivariate analyses, high miR-126 expression in tumor remained a significant independent predictor of improved disease-specific survival (HR = 0.42, CI 0.23–0.75, p = 0.004). Within different TNM-stages there was a tendency towards the same results, but with statistically significant results in stage II only (p = 0.007). High expression of miR-126 is an independent positive prognostic factor in stage I–III colon cancer. This finding may be used to identify patients in need of adjuvant chemotherapy.