Endocrine Abstracts

Objectives: Aberrances in expression and sequence of miR-146a have a well-established role in pathogenesis of papillary thyroid carcinoma (PTC). The G/C heterozygosity in rs2910164 of miR-146a underlies genetic predisposition to PTC and occurs as a somatic mutation in thyroid tumors. Deleterious function of rs2910164 consists in creation of a new variant of microRNA, resulting from the fact that a single microRNA precursor gives rise to −5p and −3p microRNAs. The S...

Objectives: Papillary thyroid carcinoma (PTC) exhibits aberrant expression of retinoic acid receptor β (RARβ), a retinoic acid-inducible transcription factor, essential for cellular growth and development. The mechanisms leading to decreased RARβ expression in tumors are unknown. We hypothesized that changes in expression of RARB, a gene encoding for RARβ, result from aberrant expression of microRNAs. We elucidated the miRNome of normal thyroid and...

Objectives: The sodium/iodide symporter (NIS) is a glycoprotein with unique ability of transporting iodine into the thyroid follicle. Apart from the importance in thyroid hormone synthesis, this function of NIS allows the use of radioactive iodine to target residual and metastatic thyroid cancer after thyroidectomy. However, 20–30% of thyroid tumors exhibit lowered expression of NIS, resulting in decreased uptake of radioiodine and inefficient post-surgical therapy. Mecha...

Objectives: Apical iodide transporter (AIT) is essential for thyroid homeostasis, functioning both as iodide transporter and a potent tumor suppressor. Its decreased levels observed in thyroid cancer underlie its progression and inefficiency of radioactive iodine treatment, used for ablation of post-operative and metastatic thyroid cancer cells. Mechanisms of AIT downregulation in cancer are largely unknown, but recent data on overexpression of microRNAs in thyroid cancer sugg...

Introduction: Papillary Thyroid Carcinoma (PTC) exhibits activation of MAPK (Mitogen-activated protein kinases) pathway, leading to uncontrolled cellular division and growth. Concomitantly, thyroid tumors exhibit aberrant expression of numerous microRNAs, which are non-coding RNAs that inhibit expression of protein-coding genes. Employing next-generation sequencing (NGS), we revealed comprehensive miRNA profiles of normal thyroid and PTC, and identified putative novel microRNA...

Type 1 deiodinase (D1) catalyses deiodination of tyroxine (T4), which leads either to synthesis of triiodothyronine or reverse triiodothyronine (rT3). Triiodothyronine (T3) regulates the expression of many tumour suppressor genes and oncogenes. We previously revealed that the expression of the whole pool of D1 transcripts was dramatically lowered in ccRCC tissues. One of the mechanism resulting in this aberration could be miRNA-mediated repress...

Introduction: 24-hydroxylase, encoded by a CYP24A1 gene, is a crucial enzyme entailed in catabolism of vitamin D. Loss-of-function mutations of CYP24A1 result in hypercalcemia, not adequately concomitant high levels of 1,25(OH)2D and low PTH levels. The variety of clinical manifestations depends on age – mutations can lead to fatal infantile hypercalcemia among neonates (typically precipitated by supplementation of vitamin D), whereas adults’ symptoms are usually mil...

Background: Risk of developing papillary thyroid carcinoma (PTC), the most frequent thyroid malignancy, is elevated up to 8.6-fold in the first-degree relatives of PTC patients, what could be explained by polygenic action of low-penetrance alleles. Since the DNA-damaging exposure to ionizing radiation is a known risk factor for thyroid cancer, polymorphisms in DNA repair genes are likely to affect this risk. Among the DNA repair proteins, the ATM–CHEK2–BRCA1 axis see...

Objectives: Papillary thyroid carcinoma (PTC) is the most common malignancy of the endocrine system. Its heritability is the highest among common cancers, as evidenced by family-based studies. Thyroid hormone receptor β gene (THRB), a known tumor suppressor, is crucial for the proper thyroid function, therefore its polymorphisms are likely to affect the risk for thyroid cancer.Aim of the study: In order to identify alleles that might modify...