The Role of miRNA Dysregulation in Thyroid Cancer Development by Targeting the Main Signaling Pathways

Thyroid cancer is one of the most common malignancies of endocrine glands, causing carcinomas, such as papillary, follicular, medullary, and anaplastic thyroid carcinomas. Due to the significance of thyroid carcinomas, identification of the main signaling pathways and  the affecting mutations has been considered by researchers. Further studies on the dysregulation of oncogenes in signaling pathways have also revealed the feedback mechanisms between oncogenes/tumor suppressor genes and miRNAs. Considering the importance of thyroid carcinoma and the important role of miRNAs, this review study aimed to introduce the main signaling pathways and the most important modified miRNAs along with an explanation for the mechanism of their functions. Generally, Changes in the main PI3K, MAPK, and TGFβ signaling pathways alone or in combination, depending on the type and severity of cancer, have essential roles in thyroid cancer initiation and progression. Dysregulation of miRNAs and the signaling pathways, based on oncogene/tumor suppressor gene feedback mechanisms, can be an aggravating factor for the thyroid cancer process. Given the confirmed role of miRNAs in tumorigenesis and our current knowledge of miRNA-related cancers, miRNAs can be used as potential biomarkers for therapeutic purposes, as well as prognostic and diagnostic agents for cancer progression.