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.