Predicting the Metastatic Potential of Papillary Thyroid Microcarcinoma Based on the Molecular Profile of Preoperative Cytology Specimens

The strategy of active surveillance for papillary thyroid microcarcinoma (PTMC) is becoming increasingly popular within the global medical community. A key criterion for selecting this strategy is the absence of any signs of lymphogenic or distant metastases. The present study assessed the diagnostic accuracy of molecular genetic markers for predicting the metastatic potential of patients with PTMC. We evaluated the expression levels of 33 molecular genetic markers in cytology samples from 92 patients with PTMC and confirmed histological diagnosis. Among these patients, 32 had metastases to regional cervical lymph nodes. Our findings revealed the upregulated expression of the HMGA2, TIMP1, and FN1 genes, as well as microRNA-146b, in patients with metastatic PTMC. Conversely, we found the downregulated expression of miRNA-7 and -148b in metastatic tumors. In metastatic tumors, significant reductions were observed in DIO1 activity (11-fold), TFF3 gene expression (8-fold), TPO expression (4-fold), and SLC26A7 expression (2.6-fold). All the markers exhibited high sensitivity (84.5–90.6%) in detecting metastatic PTMC, although the specificity proved to be low. The use of molecular markers to predict lymphogenic metastatic spread in patients with PTMC could enhance existing risk grading systems. Such assessments can already be applicable at the preoperative stage.