Prognostic significance of microRNA-16 expression in human colorectal cancer.

BACKGROUND: MicroRNAs (miRNAs), small noncoding RNAs, have been reported to be highly involved in the formation and progression of all types of human cancer including colorectal cancer (CRC). Therefore, miRNAs are also potential prognostic biomarkers in CRC patients. The aim of this study was to detect the expression of miR-16 in human CRC tissues and investigate its clinicopathologic or prognostic significance.

METHODS: TaqMan quantitative reverse transcription polymerase chain reaction (qRT-PCR) assay was performed to determine the expression of miR-16 in 143 primary CRC tissues and 18 corresponding normal colonic mucosa from patients who had undergone surgery. The association of miR-16 expression with clinicopathologic features of CRC patients was statistically analyzed. Kaplan-Meier analyses were used to assess patient survival. Univariate and multivariate Cox analyses were performed.

RESULTS: The relative level of miR-16 in 18 CRC tissues was significantly lower than that in corresponding normal colonic mucosa (p < 0.001). Statistical analyses revealed that the status of miR-16 expression was closely associated with tumor differentiation, lymph node metastasis, L category, V category, TNM stage, and tumor recurrence of CRC (p = 0.001, 0.003, 0.001, 0.005, 0.003, and 0.017, respectively). Kaplan-Meier analyses indicated that patients with low-miR-16 had lower 5-year overall survival than those with high-miR-16 (31.2 vs. 58.3 %; p = 0.0012). Multivariate Cox regression analyses indicated that the status of miR-16 expression might be an independent prognostic factor for CRC patients (hazard ratio 1.67; 95 % confidence interval 1.22-2.54; p = 0.018).

CONCLUSIONS: Down-regulation of miR-16 plays critical roles in CRC progression. Low miR-16 expression is an independent factor predicting a poor prognosis for CRC patients.