Background/Aim: Papillary thyroid cancer (PTC) is the most common endocrine malignancy with a rising incidence. There is a need for a non-invasive preoperative test to enable better patient counselling. The aim of this systematic review was to investigate the potential role of circulating microRNAs (miRNAs) in the diagnosis and prognosis of PTC. Materials and Methods: A systematic literature search was performed using MEDLINE, Cochrane, and Scopus databases (last search date was December 1, 2021). Studies investigating the expression of miRNAs in the serum or plasma of patients with PTC were deemed eligible for inclusion. Results: Among the 1,533 screened studies, 39 studies met the inclusion criteria. In total, 108 miRNAs candidates were identified in the serum, plasma, or exosomes of patients suffering from PTC. Furthermore, association of circulating miRNAs with thyroid cancer-specific clinicopathological features, such as tumor size (13 miRNAs), location (3 miRNAs), extrathyroidal extension (9 miRNAs), pre-vs. postoperative period (31 miRNAs), lymph node metastasis (17 miRNAs), TNM stage (9 miRNAs), BRAF V600E mutation (6 miRNAs), serum thyroglobulin levels (2 miRNAs), 131 I avid metastases (13 miRNAs), and tumor recurrence (2 miRNAs) was also depicted in this study.
Conclusion: MiRNAs provide a potentially promising role in the diagnosis and prognosis of PTC. There is a correlation between miRNA expression profiles and specific clinicopathological features of PTC. However, to enable their use in clinical practice, further clinical studies are required to validate the predictive value and utility of miRNAs as biomarkers.Thyroid cancer is the 20 th most common cancer in the UK, and the incidence rates are projected to rise to 74% by the year 2035 (1). Papillary thyroid carcinoma (PTC) is the most common histological type, accounting for approximately 80% of the cases (2). Although, the vast majority of patients presenting with thyroid nodules that are benign, the ability to characterize the malignant nodules is quite important to ensure appropriate patient counselling when discussing curative therapy and the extent of the primary resection (3).