Assessment of cyclooxygenase-1 and 2 gene expression levels in chronic autoimmune thyroiditis, papillary thyroid carcinoma and nontoxic nodular goitre

Abstract

Introduction: The cyclooxygenases are a group of enzymes catalyzing the formation of prostaglandins fro arachidonic acid. Cyclooxygenase-1 (COX-1) is a constitutive form, thought to be a "housekeeping gene", with constan levels of expression in most tissues. COX-1 expression in the thyroid gland, except for medullary thyroid carcinoma, ha not been a subject of much interest. Cyclooxygenase-2 (COX-2) can be expressed in response to various stimuli, suc as mitogens, hormones, cytokines, growth factors. The product of COX-2 activity has been implicated in carcinogenesis Recent studies have shown that up-regulation of COX-2 is associated with numerous neoplasms. Hereby, we present study analysing COX-1 and COX-2 expression in papillary thyroid carcinoma (PTC), Hashimoto thyroiditis (HT) an nontoxic nodular goitre (NNG) in fine needle aspiration biopsy (FNAB) washouts and in postoperative tissue Material and methods: Cytological specimens from 120 patients (105 females and 15 males) have been studied including patients with HT, PTC and NNG. Moreover, we have examined postoperative tissue specimens from 5 patients with PTC and NNG The methods of molecular analysis have included extraction of total RNA from FNAB cytological material an postoperative tissues, spectrophotometric assessment of the RNA purity, cDNA synthesis in reverse transcriptio reaction and an analysis of genes expression data by real-Time PCR Results: The performed analysis has revealed statistically significant higher expression level of the COX-2 gene i PTC group, in comparison with HT and NNG groups (in both cytological and postoperative material) In PTC patients, COX-2 gene expression levels in the material obtained by FNAB were similar to those in th postoperative thyroid tissue No correlations between COX-2 gene expression level and TNM staging in PTC samples have been observed There were no correlations between COX-2 expression and anti-TPO antibodies level, or patient's sex or age in th studied groups. Also, there were no correlations of COX-1 gene expression level among PTC, HT and NNG groups Conclusions: Our results suggest that COX-2 gene does not participate in the mechanisms involved in molecula association of HT with PTC. However, in case of PTC itself, it may play some role in neoplastic transformation.