Abstract
Introduction.: There is no effective and reliable biomarker to distinguish benign thyroid nodules (BTN) from papillary thyroid carcinomas (PTC). In this study we analyzed a set of four miRNA molecules in plasma of patients with papillary thyroid cancer, benign nodules and healthy controls to identify miRNA molecules that may be markers of PTC.Aim.: We aimed to investigate the dysregulation of plasma miRNAs in PTC and evaluate the diagnostic value for differentiation of PTC from BTN. Methods.: The expression levels of 4 miRNAs (miR-221, miR-222, miR-146b, miR-21) were measured in 48 PTC patients before thyroidectomy and again after thyroidectomy in a subgroup of 36 patients. Preoperative and postoperative plasma miRNA expression levels were compared with baseline levels established in plasma from the heathy controls group (N=57) and patients with BTN (N=22). MicroRNA-222 and miR-146b, miR-221, miR-21 were included in a panel because they all reportedly were overexpressed in PTC compared to benign nodules or normal thyroid tissue.Results.: Compared with baseline levels in the healthy controls group, miR-221, miR-222, miR-146b, miR-21 levels were significantly higher in the preoperative PTC group (P <0.0001, P=0.002, P=0.028, P =0.021, respectively). A significant reduction in miR-21 expression was observed in postoperative PTC patients. MiR-21 decreased by 5.98-fold (P=0.046) in post- operative samples compared with preoperative samples in the PTC patients.In comparison MiRNRs expression levels in BTN group with healthy controls, miR-221, miR-21 expression levels were significantly higher in the BTN group (P=0.003, P=0.048, respectively). No significant difference was observed between the preoperative PTC group and the preoperative BTN group with regard to the expression of these four miRNA’s. Conclusions: The expression levels of miR-222, miR-146b in plasma were significantly higher in patients who had PTC than in healthy volunteers, whereas levels of miR-221, miR-21 in plasma were significantly higher in patients who had either PTC or BTN before thyroidectomy than in healthy volunteers. Furthermore, miR-21 showed a significant reduction of expression levels after thyroidectomy in PTC patients. However, value of these four miRNAs is still limited in differential diagnosis of PTC and benign nodules.
BRAFV600E mutation influences hypoxia-inducible factor-1α expression levels in papillary thyroid cancer