Introduction: Papillary thyroid carcinoma (PTC) is the most common type of thyroid malignancy. For the majority of patients with PTC, the prognosis is very good; however, up to 20% of patients suffer disease recurrence. Currently, the risk stratification for PTC recurrence is based on clinicopathological features which have limited prognostic value. Identification of molecular biomarkers of PTC recurrence such as protooncogene BRAF and miRNAs may help to improve risk-stratified patient management.
Objective: The aim of this study was to detect BRAFV600E mutation and identify miRNA biomarkers for PTC recurrence.
Methods: We selected 3 miRNA (miRNA- 146b, -222 and -21) and measured the expresion levels of these miRNAs in patients with recurrent PTC (Rc-PTC) and without recurrence (NRc-PTC). 106 NR-PTC and 60 Rc-PTC FFPE samples were analysed for selected miRNAs. 114 FFPE PTC samples (31 Rc-PTC and 83 NR-PTC) were analysed for BRAFV600E mutation.
Results: The expression levels of all three miRNAs were significantly increased in PTC when compared to healthy thyroid tissue. miRNA-146b expresion was extremely elevated with 55.6-fold over-expression in PTC (P<0.001). miRNA-222 and -21 were over-expressed 13.8-fold and 3.7-fold, respectively (P=0.001 and P=0.16). In Rc-PTC and NRc-PTC groups miRNA-21, -146b and -222 were significantly differently expressed with 1.4- fold (P=0.006), 1.8-fold (P=0.007) and 2.1-fold (P<0.001) higher expresion in NRc-PTC compared with Rc-PTC tissues. 114 FFPE PTC samples were analysed for BRAFV600E mutation and 66 of them (57.9%) were shown to be positive. Subsequently, DNA samples from Rc-PTC and NR-PTC groups were analysed for BRAFV600E mutation and this mutation was found in 54.8% (17/31) of Rc-PTC samples and 59.0% (49/83) of NR-PTC samples. There was no signifficant difference between these groups (P=0.686).
Conclusion: These results suggest that miRNA-21, miRNA-222, miRNA-146b might be potential biomarkers for PTC recurrence. BRAF mutation is not associated with PTC recurrence.
20 - 23 May 2017
European Society of Endocrinology