MicroRNAs – promising molecular markers for detecting cancer in thyroid nodules

Thyroid nodules are one of the most common thyroid diseases. The prevalence of thyroid nodules is estimated to be 2–65% depending on the detection methods. Yet despite the high frequency of thyroid nodules only about 5–10% of such nodules are malignant. Fine needle aspiration cytology of the thyroid nodule is currently the primary diagnostic tool for determining the nature of a thyroid nodule. Now, the fine needle aspiration biopsy is the gold standard for diagnosing thyroid cancer but in 30% of cases the cytological conclusion is uncertain. Cytological research is not enough to diagnose benign and malignant tumors. The need to improve the effectiveness of fine needle aspiration biopsy findings led to the search for new diagnostic biomarkers and the creation of diagnostic panels on their basis for their application in the diagnosis of uncertain nodules. Determination of molecular markers in the thyroid aspirate will allow to differentiate benign and malignant tumors more accurately at the preoperative stage and reduce the number of inappropriate surgery. The review article presents the characteristics of MicroRNAs, allowing them to be used in preoperative diagnosis of thyroid nodules. Diagnostic panels based on gene mutations and MicroRNA expression demonstrating high sensitivity and specificity of these methods are also indicated. Analysis of literature indicates that molecular analysis of fine needle aspiration genetic material from thyroid nodal formations demonstrates great prospects of prognosis, diagnosis and treatment of thyroid cancer. However, there is no sufficient evidence to recommend or to prohibit of utilization this molecular testing during the cytological conclusion of indeterminate thyroid nodules. Molecular analysis (MicroRNA) is a perspective method for evaluation of thyroid nodal formations with indeterminate cytology, however, this method requires further study and improvement.