Diagnostic value of the candidate microRNAs in thyroid fine-needle aspiration biopsy (FNAB) samples

Background Thyroid cancer (TC) is known to be the most common endocrine malignancy with an incidence rate which has increased by 2.3-fold over the past 30 years. Approximately, 30% of the thyroid fine-needle aspiration biopsy (FNAB) outcomes are indecisive. Moreover, researchers recognized multiple differentially expressed microRNAs (miRNAs) as candidate diagnostic markers for thyroid nodules. The purpose of this study was to identify thyroid tumor-associated miRNAs in FNAB with the capacity to be developed as unique biomarkers. Materials and methods According to the study design, a quantitative real time reverse transcription polymerase chain reaction (qRT-PCR) was applied to evaluate the expression levels of nine miRNAs (Let7, miR-34a, miR-146b, miR-221, miR-151, miR-155, miR-181b, miR-222 and miR-375) among 224 FNA samples as the training set. Results The findings of this study revealed that miR-181b and miR-146b are the best predictors to diagnose benign thyroid FNA samples from malignant samples. However, the remaining miRNAs were co-expressed and had no significant effect on the predictor model. On the other hand, sensitivity and specificity of miR-181b and miR-146b were reported at 83.0%-83.0% and 83.0%-66.0%, respectively. Conclusions According to the results of this study, miR-146b and miR-181b might be considered as adjunct markers contributing to thyroid FNAB in tumor types. In addition, miR-146b and miR-181b were recognized as biomarkers for discriminating benign thyroid nodules from malignant ones. It is suggested that further prospective clinical trials be conducted to evaluate the accuracy of such findings in a larger cohort and determine the clinical uses.