Downregulation of miR-195 correlates with lymph node metastasis and poor prognosis in colorectal cancer.

miR-195, one of the miR-16/15/195/424/497 family members, has been shown to play an important role in tumorigenesis, as a tumor suppressor. Here, we assess miR-195 expression in colorectal cancer, which has not been investigated before, and its clinical significance including survival analysis. The in vivo significance of expression of miR-16/15/195/424/497 in matched normal and tumor tissues of colorectal cancers was evaluated using a quantitative real-time RT-PCR. Two colorectal cancer cell lines and 85 colorectal cancer and paired normal patient samples with detailed clinical follow-up information were selected. The statistical significance of these markers for disease prognosis was evaluated using a two-tailed, paired Wilcoxon test. A Kaplan-Meier survival curve was generated following a logrank test. As a result, miR-424 was significantly over-expressed, while miR-15a, miR-15b, miR-16, and miR-195 were downregulated in tumors compared with normal colorectal samples (all P < 0.01). Reduced expression of miR-195 occurred more often in patients with lymph node metastasis and advanced tumor stage (all P < 0.01). Kaplan-Meier survival analysis indicated that patients with reduced miR-195 had a poor overall survival (P < 0.01). Moreover, the multivariate analysis showed that reduced expression of miR-195 was an independent predictor of overall survival. Our data indicate the potential of miR-195 as a novel diagnostic or prognostic biomarker for CRC.