ESPE Abstracts

Background: Many epigenetic factors, including microRNAs, are involved in the process of changing gene expression. MiRNAs are small non-coding RNA molecules that regulate gene translation by silencing or degrading target mRNAs. They are recognized as novel diagnostic and prognostic biomarkers for many diseases. Patients with autoimmune thyroid diseases are more likely to develop nodules in the thyroid tissue, and Hashimoto's thyroiditis and Graves’ disease predispose to thyroid cancer. We evaluated the concentrations of microRNA molecules (miR-15a-5p, miR-126-3p, miR-142-5p, miR-21-5p, miR-150-5p) in the blood of children with thyroid disorders, considering their predisposition to develop cancer.

Aim: The aim of this study is to evaluate selected epigenetic elements by analyzing the levels of miR-15a-5p, miR-126-3p, miR-142-5p, miR-150-5p, miR- 21-5p in the blood of pediatric patients with Graves’ disease (n = 25), Hashimoto's thyroiditis (n = 26) and thyroid nodular disease (n = 20) compared to a control group of healthy children (n = 17).

Materials and Methods: The study consists of groups of children and adolescents aged 10-18 years with autoimmune thyroid disease, with thyroid nodular disease compared to a control group. The miR-15a-5p, miR-126-3p, miR-142-5p, miR-21-5p and miR- 150- 5p molecules were determined by immunoenzymatic assay using BioVendor reagents.

Results: There is statistically significant decrease in the expression of the miR-15a-5p in children with Graves’ disease (21.61 vs. 50.22 amol/ul, P = 0.03) and in patients with thyroid nodular disease compared to controls (20.23 vs. 50.22 amol/ul, P = 0.04). Higher levels of the miR-142-5p molecule are found in patients with thyroid disease (with GD- 3.8 vs 3.14 amol/ul, P = 0.01; with HT- 3.7 vs 3.14 amol/ul, P = NS, with thyroid nodular disease- 4.16 vs 3.14 amol/ul, P = 0.04). Lower levels of miR- 126-3p were noted in the GD group compared to the control group (7.09 vs 7.24 amol/ul, P = 0.02). No statistically significant changes in the expression of miR-150-5p and miR-21-5p molecules were observed in the study groups.

Conclusions: 1. Overexpression of the miR-142-5p molecule occurs in children and adolescents with thyroid diseases. 2/. Decreased blood levels of miR- 15a-5p predispose to the formation of focal lesions in the thyroid gland. 3/. Identifying lower expression of the miR- 126-3p molecule in the blood of children with GD require careful follow-up for the development of focal lesions in the thyroid gland and evaluation for their potential malignancy.