Decreased serum microRNA-206 level predicts unfavorable prognosis in patients with melanoma.

BACKGROUND AND PURPOSE MicroRNA-206 (miR-206) acts as a tumor suppressor in melanoma cell lines. However, its clinical significance remains unclear. The aim of this study was to detect the serum level of miR-206 in patients with melanoma and to determine the feasibility of using it as a noninvasive prognostic biomarker. METHODS Expression levels of miR-206 in serum samples from 60 patients with melanoma and 30 healthy controls were detected by real-time quantitative polymerase chain reaction (q-PCR). RESULTS Expression levels of miR-206 in serum samples from patients with melanoma were significantly lower than those in healthy controls (P<0.001). In addition, low serum miR-206 level was more frequently observed in patients with two or more metastatic sites (P=0.02). Its serum level was also significantly associated with the response to treatment (P=0.01). Moreover, melanoma patients with low serum miR-206 levels had higher clinical stage than those with high serum miR-206 levels (P<0.001). Furthermore, melanoma patients with low serum miR-206 level had a dramatically shorter 5-year overall and disease-free survival than those with high serum miR-206 level (both P=0.001). Multivariate analysis also identified the serum miR-206 level as an independent marker for both 5-year overall and disease-free survivals (both P=0.01) in patients with melanoma. CONCLUSIONS Our results offer the convincing evidence that miR-206 may be implicated in aggressive progression of melanoma. More importantly, the serum level of miR-206 may be a noninvasive prognostic biomarker for the patients with melanoma.