Downregulation of lncRNA H19 (H19) expression is associated with an unfavorable prognosis in some cancers. However, little was known as to whether there was an association between H19 and minimally invasive follicular thyroid carcinoma (MI-FTC). In our study, we used quantitative real-time polymerase chain reaction (qRT-PCR) to determine H19 expression in 186 patients with MI-FTC who underwent initial surgery. Of the 186 patients with MI-FTC, 21 patients show distant metastasis （M+）at the initial operation established the diagnosis of MI-FTC. Of the 165 patients who did not show distant metastasis at diagnosis during the follow-up period (≥10 years), 28 patients undergone M+ and 137 patients has no distant metastasis（M-）after the initial operation. Low H19 expression was associated with large tumor size, vascular invasion, and distant metastasis. Univariate analysis showed that gender (male), age (45 years or older), primary tumor size (4 cm or more), vascular invasion and H19 level (<1.12) were significant prognostic factors related to postoperative distant metastases. Multivariate analysis showed that age, primary tumor size (4 cm or more) and vascular invasion was a significant prognostic factor for survival. Patients with low H19 expression showed a poorer outcome in MI-FTC patients. Receiver-operating characteristic (ROC) curve analysis demonstrated H19 could distinguish M+ from M- patientswith a value of area under the curve (AUC). Our findings suggest that H19 is a potential prognostic factor for evaluating prognosis and the metastatic potential of MI-FTC at an initial operation stage.

Downregulation of lncRNA H19 (H19) expression is associated with an unfavorable prognosis in some cancers. However, little was known as to whether there was an association between H19 and minimally invasive follicular thyroid carcinoma (MI-FTC). In our study, we used quantitative real-time polymerase chain reaction (qRT-PCR) to determine H19 expression in 186 patients with MI-FTC who underwent initial surgery. Of the 186 patients with MI-FTC, 21 patients show distant metastasis （M+）at the initial operation established the diagnosis of MI-FTC. Of the 165 patients who did not show distant metastasis at diagnosis during the follow-up period (≥10 years), 28 patients undergone M+ and 137 patients has no distant metastasis（M-）after the initial operation. Low H19 expression was associated with large tumor size, vascular invasion, and distant metastasis. Univariate analysis showed that gender (male), age (45 years or older), primary tumor size (4 cm or more), vascular invasion and H19 level (<1.12) were significant prognostic factors related to postoperative distant metastases. Multivariate analysis showed that age, primary tumor size (4 cm or more) and vascular invasion was a significant prognostic factor for survival. Patients with low H19 expression showed a poorer outcome in MI-FTC patients. Receiver-operating characteristic (ROC) curve analysis demonstrated H19 could distinguish M+ from M- patientswith a value of area under the curve (AUC). Our findings suggest that H19 is a potential prognostic factor for evaluating prognosis and the metastatic potential of MI-FTC at an initial operation stage.