Differential expression of microRNAs in aggressive and non-aggressive papillary thyroid carcinomas

Introduction Papillary thyroid carcinoma is the most common malignancy of the thyroid gland. The usual treatment is surgery, followed by radioactive iodine treatment in advanced cases. Approximately 13% of patients experience local or distant disease. Despite the identification of several risk factors, it is difficult to predict the patients in which metastases is likely to recur. MicroRNAs are short non-coding RNAs that play a central role in the regulation of gene expression by binding to target genes. They are related to various thyroid tumours. The study aimed to evaluate the expression of microRNAs between aggressive and non-aggressive papillary thyroid carcinomas. Materials and methods The computerized database-of Rabin Medical Center-of 10 patients with papillary thyroid carcinoma who underwent treatment and experienced recurrence between 2005 and 2011 was reviewed. They were compared with a control group of 10 patients with similar demographic characteristics who did not experience disease recurrence. Formalin-fixed, paraffin-embedded tissue samples were obtained from all 20 patients. Total RNA was extracted and microRNA expression profiles between the two cohorts were compared. Results and discussion We identified 80 microRNAs with differential expression in papillary thyroid carcinoma when comparing aggressive versus non-aggressive patient samples. Most microRNAs were not described in thyroid cancer. Several of these could be potential biomarkers for future diagnosis, and their identification could possibly be a first step for more effective therapeutics. Conclusion In conclusion, we identified a group of 80 miRNAs that were differently expressed in aggressive and non-aggressive papillary thyroid carcinomas. Expression of miR-483-5p was found to be the most significant in terms of aggressive behaviour of papillary thyroid carcinomas.