Downregulation of miR-381 is associated with poor prognosis in papillary thyroid carcinoma.

Circulating microRNAs (miRNAs) are potential biomarkers for papillary thyroid carcinoma (PTC). The aim of this study was to evaluate the diagnostic and prognostic value of serum miR-381 in PTC. A total of 87 patients with PTC, 50 cases with benign thyroid nodules (BTN) and 50 healthy volunteers were enrolled. The expression levels of serum miR-381 were measured using quantitative reverse transcription-polymerase chain reaction (qRT-PCR). The results indicated that serum miR-381 expression was significantly decreased in PTC patients compared to that of BTN patients or healthy controls. Moreover, serum miR-381 showed good performance to differentiate PTC cases from controls. Next, reduced serum miR-381 expression was positively correlated with aggressive clinical features and shorter overall survival. Furthermore, serum miR-381 levels were greatly elevated in 21 patients with advanced-stage (stage III/IV) PTC after surgery. Finally, univariate and multivariate Cox regression analysis confirmed that miR-381 in serum was an independent prognostic indicator for OS in PTC patients. Collectively, serum miR-381 might serve as a non-invasive biomarker for the diagnosis and prognosis of PTC.