Expression of miRNAs in Papillary Thyroid Carcinomas Is Associated with BRAF Mutation and Clinicopathological Features in Chinese Patients

MicroRNAs (miRNAs) dysregulation has been shown to play a critical regulatory role in papillary thyroid carcinomas (PTCs). BRAF mutation is associated with poor clinicopathological outcomes in PTC. In order to identify a possible association between dysregulated miRNA expression and BRAF mutation as well as clinicopathological features in Chinese patients with PTC, we examined the expression levels of five reported dysregulated miRNAs (miRNA-221, miRNA-222, miRNA-146b, miRNA-181, and miRNA-21) and determined BRAF mutation status in 52 patients with PTC and 52 patients with benign thyroid nodules (BTNs). The expression levels of all five miRNAs were significantly increased in PTC when compared to BTN. The BRAF mutation occurred more frequently in PTC cases with advanced TNM stage. Importantly, miRNA-221, miRNA-222, miRNA-146b, and miRNA-181 expression levels were significantly higher in PTC patients with BRAF mutation. In addition, enhanced expression of miRNA-221 and miRNA-222 was found in patients with cervical lymph node metastasis and advanced TNM stage. Increased expression of miRNA-221 and miR-181 was evidenced in patients with larger tumors. These findings showed a potential role of this distinct profile of miRNAs in differentiating PTC from BTN. BRAF mutation might regulate or interact with miRNA in the pathogenesis and progression of PTC.