Downregulation of microRNA-100 correlates with tumor progression and poor prognosis in colorectal cancer.

Dysregulation of microRNA-100 (miR-100) has been shown to be involved in cancer tumorigenesis and progression of several cancer types. However, its expression patterns in tumors are controversial. The aim of this study was to investigate the expression and clinical significance of miR-100 in colorectal cancer (CRC). Quantitative real-time PCR was used to analyze the expression of miR-100 in 138 pairs of human CRC and adjacent normal tissues. The prognostic values of miR-100 in CRC were also analyzed. The results showed that the miR-100 expression was significantly downregulated in CRC tissues when compared to adjacent normal tissues (P<0.001). Also, low miR-100 expression was observed to be significantly correlated with larger tumor size (P=0.023), higher incidence of lymph node metastasis (P=0.009), and advanced TNM stage (P=0.016). More importantly, Kaplan-Meier analysis showed that CRC patients with low miR-100 expression tended to have shorter overall survival. In multivariate analysis stratified for known prognostic variables, low miR-100 expression was identified as an independent prognostic factor for overall survival. In conclusion, our data indicated for the first time that the downregulation of miR-100 was associated with advanced clinical features and poor prognosis of CRC patients, suggesting that miR-100 downregulation may serve as an unfavorable prognostic biomarker in CRC.