The prognostic value of microRNA-126 and microvessel density in patients with stage II colon cancer: results from a population cohort

BACKGROUND: Angiogenesis plays a pivotal role in malignant tumour growth and the metastatic process. We analysed the prognostic value of two angiogenesis parameters, microRNA-126 (miRNA-126) and microvessel density (MVD), in a population based cohort of patients operated for stage II colon cancer. METHODS: A total of 560 patients were included. Analyses were performed on formalin fixed paraffin embedded tissue from the primary tumours. The analysis of miRNA-126 expression was performed by qPCR. Microvessels were visualised by CD105 and quantified in hot spots using a light microscope. The analyses were correlated with recurrence-free cancer specific survival (RF-CSS) and overall survival (OS). RESULTS: Low miRNA-126 expression was significantly correlated to T4, high malignancy grade, tumour perforation, fixation, and the presence of microsatellite instability. A prognostic impact on OS was detected in the simple analysis favouring patients with high miRNA-126 expression p = 0.03, and borderline significance as to RF-CSS, p = 0.08. The impact on OS demonstrated borderline significance in a following multiple Cox regression analysis, hazard ratio 0.76 (95% confidence interval, 0.58-1.00), p = 0.051. The MVD estimate was not associated with either RF-CSS, p = 0.49, or OS, p = 0.94. CONCLUSION: The current population based study of patients operated for stage II colon cancer demonstrated correlations between several prognostic unfavourable characteristics and miRNA-126 and argues for a possible prognostic impact on overall survival. An influence on survival by the MVD estimate was not detected.