Predicting Risk of Lymph Node Metastasis in Papillary Thyroid Cancer Using miRNAs and Clinicopathological Features

This study investigates potential prognostic values in models created with clinicopathological features and expression profiles of miRNAs known for their critical roles in papillary thyroid carcinoma (PTC) for lymph node metastasis (LNM) in PTC cases. Forty-seven lymph node-metastatic PTC patients and 46 non-metastatic patients were included. Using RT-PCR, miR-21, miR-146b, miR-221, and miR-222 expression was analyzed in carcinoma tissues and metastatic lymph nodes of the same PTC patients and carcinoma tissues of non-metastatic PTC patients. MiR-146b (p < 0.001) and miR-221 (p = 0.009) were overexpressed in metastatic PTCs compared to non-metastatic PTCs. The miRNA expression profiles were similar in the lymph nodes and primary cancer of metastatic PTCs. In the presence of larger tumors (> 1 cm) in metastatic PTCs, miR-146b and miR221 were overexpressed in the tumor tissue (p = 0.036), while miR-222 was overexpressed in metastatic lymph nodes (p = 0.035). miR-146b was also upregulated in lack of peritumoral lymphocyte infiltration (p = 0.006). In conclusion, our findings suggest that the overexpression of miR-146b and miR-221 in PTC tissues may be associated with lymph node metastasis and a poorer prognosis. Furthermore, the presence of larger tumors and increased levels of intratumoral fibrosis in non-metastatic PTC patients could indicate a poor prognosis.