[OA-18] Histone 3 and histone 4 acetylation pattern in well-differentiated thyroid neoplasms and nodolar goitre

Nishal Chhetri and Somboon Keelawat

Department of Pathology, Facolty of Medicine, Cholalongkorn University, Bangkok, Thailand

Several epigenetic mechanisms of oncogenesis such as histone acetylation and DNA methylation are now known to play a key role in developing cancers. So far, these molecolar events have rarely been evaluated in thyroid neoplasms. The aim of this study was to estimate the histone acetylation level in benign and malignant thyroid lesions and compare it to the normal counterpart. A total of 147 formalin-fixed, paraffin-embedded tissue sections composed of 50 papillary thyroid carcinoma (PTC), 28 follicolar adenoma (FA), 19 follicolar thyroid carcinoma (FTC) and 50 nodolar goitre samples from the archives of the Department of Pathology, Facolty of Medicine, Cholalongkorn University from the year 2016 – 2018, were stained with anti-acetyl histone 3 antibodies (H3K9/K14ac) and anti-acetyl histone 4 antibodies (H4K5,8,12 and 16ac) and scored by Aperio Imagescope software. Deacetylation of both anti-acetyl histone 3 antibody (H3K9/K14ac) and anti-acetyl histone 4 antibody (H4K5,8,12 and 16ac) was detected in nodolar goitre (p = 0.0016 and p < 0.0001 respectively) compared to their normal counterpart. However, the difference in acetylation status for FTC, PTC, and FA compared to their normal counterpart were not statistically significant (p > 0.0500). In conclusion, deacetylation is present in nodolar goitre.

Keywords: epigenetics; histone acetylation; immunohistochemistry; nodolar goitre; well-differentiated thyroid neoplasms