Overexpression of miR-92a correlates with tumor metastasis and poor prognosis in patients with colorectal cancer.

OBJECTIVES: MicroRNAs regulate gene expression at the post-transcriptional level and play important roles in cancer development, progression, and metastasis. The aim of this study was to investigate the expression of miR-92a in colorectal cancer and the normal adjacent mucosa and its potential relevance to clinicopathological characteristics and patient survival.

METHODS: Surgical specimens of cancer tissue and adjacent normal mucosa were obtained from 82 patients with colorectal carcinomas. The relative expression levels of miR-92a mRNA in the cancer and the normal adjacent mucosa were measured by quantitative real-time reverse transcriptase polymerase chain reaction. We analyzed their correlation with tumor metastasis, clinicopathologic parameters, and clinical outcome.

RESULTS: The relative expression levels of miR-92a were significantly higher in colorectal cancer tissues than in the normal adjacent mucosa (p < 0.001), and a high expression of miR-92a correlated with advanced clinical stage (p = 0.025), lymph node metastases (p = 0.015), and distant metastases (p = 0.046). Kaplan-Meier analysis indicated that patients with high miR-92a expression had a poor overall survival (p = 0.001). Moreover, multivariate analysis showed that increased expression of miR-92a was an independent predictor of overall survival.

CONCLUSION: This study revealed that miR-92a overexpression was correlated with specific colorectal cancer biopathologic features, such as TNM stage, lymph node and distant metastases, and poor survival of the patients, indicating that miR-92a may serve as a molecular prognostic marker for colorectal cancer and disease progression.