MiR-324-5p assists ultrasonography in predicting lymph node metastasis of unifocal papillary thyroid microcarcinoma without extracapsular spread

Ultrasonography is the first choice of lymph node metastasis (LNM) detection which is crucial for therapeutic options of papillary thyroid cancer (PTC). However, the sensitivity of ultrasonography in detecting LNM of PTC is relatively low; especially in central LNM. MiR-324-5p has been reported to play important roles in the metastasis of various cancers. To explore the relationship between miR-324-5p and LNM in PTC, quantitative real-time polymerase chain reaction was performed in PTC tissue and fine needle aspiration (FNA) washout successively. Its correlation with LNM of PTC was analyzed. The clinicopathological and sonographic factors relating to LNM were also studied. Additionally, the function assay of miR-324-5p in PTC cells was conducted. Current study demonstrated that age was an independent protective factor and multifocality, advanced TNM stage, increased transverse diameter of thyroid nodule, ultrasound suspected LNM were independent risk factors of LNM. MiR-324-5p promoted proliferation, migration and invasion of PTC cell line. MiR-324-5p could serve as a candidate predictor along with ultrasonography in predicting LNM, especially central LNM of unifocal papillary thyroid microcarcinoma without extracapsular spread.