Results
Title

Expression of iodine metabolism genes in human thyroid tissues: evidence for age and BRAF<sup>V600E</sup> mutation dependency.

Authors

Espadinha, Carla; Santos, Jorge Rosa; Sobrinho, Luís G.; Bugalho, Maria João

Abstract

Context Children present a higher susceptibility to developing thyroid cancer after radioiodine exposure and also a higher frequency of functional metastases than adults. Objective To assess the mRNA expression of the sodium/iodide (Na /I−) symporter (NIS), the Pendred syndrome gene (PDS), thyroperoxidase (TPO), thyroglobulin (Tg) and TSH receptor (TSH-R) in normal thyroid tissues (NTTs) and papillary thyroid carcinomas (PTCs) among different age groups. Methods Analysis included 59 samples: 21 NTTs and 38 PTCs, of which 21 were the classic type (CPTC) and 17 the follicular variant (FVPTC). Patients were divided into three age groups: I ( n = 16) 5–21 years, II ( n = 13) 22–59 years, and III ( n = 10) 60–91 years. The relative mRNA expression of the five target genes was determinate by quantitative reverse transcription polymerase chain reaction (QRT-PCR). Results Expression of all genes was significantly higher in NTTs than in PTCs, and it was not age dependent in the NTT group. Among PTCs, the mean expression of PDS, TPO and TSH-R was significantly lower in group II than in group I. PDS, TPO and Tg expression was significantly lower in classic PTCs than in FVPTCs. The difference was related to a higher frequency of the BRAFV600E mutation in the former group. Conclusions The finding of higher PDS, TPO and TSH-R mRNA expression in paediatric vs. adult primary tumour tissues supports the hypothesis that this might contribute to the increased functional activity of metastases in the paediatric group. The finding that mRNA expression of the target genes in NTT was not age dependent does not provide an explanation for the higher susceptibility in the paediatric group.

Subjects

IODINE; GENE expression; METABOLISM; TISSUES; THYROID cancer; GENETIC mutation

Publication

Clinical Endocrinology, 2009, Vol 70, Issue 4, p629

ISSN

0300-0664

Publication type

Academic Journal

DOI

10.1111/j.1365-2265.2008.03376.x