title: Genetic investigation of FOXE1 polyalanine tract in thyroid diseases: new insight on the role of FOXE1 in thyroid carcinoma.
abstract: FOXE1 polyalanine tract (poly-Ala) has been associated with thyroid dysgenesis. Recently, the SNP (rs1867277:-238G>A) within the FOXE1 5'UTR was involved in the genetic susceptibility to thyroid cancer (TC). In the aim to assess the influence of FOXE1 poly-Ala length on the genetic susceptibility to TC and autoimmune thyroid diseases (AITD), a case-control design (including 261 Tunisian AITD, 170 Spanish TC and respectively 171 and 218 matched healthy subjects) was performed. The effect of Ala length and rs1867277 alleles on FOXE1 expression was investigated by mRNA relative real time quantification on 8 papillary thyroid carcinoma (PTC) and 10 Graves' disease (GD) genotyped thyroid biopsies. The fluorescent genotyping of poly-Ala polymorphism revealed nine alleles (from 12 to 22 repetitions). The association of poly-Ala polymorphism with AITD was rejected (Pc>0.05). However, a significant association was found with TC. In addition, the genotypic distributions revealed the predispositional effect of the 16/16 genotype (OR = 2.71; 95%CI: 1.36-5.42; p=0.001) and the protector effect of the 14/14 genotype (OR= 0.46; 95%CI: 0.29-0.72; p=0.003). The quantification studies reveal that FOXE1 transcripts were less abundant in PTC than GD samples. Moreover, FOXEI gene was 4,8 fold less expressed among PTC protected patients compared to homozygous 16/16-A/A. In conclusion, by exploring the poly-Ala polymorphism, we confirmed the involvement of {\it FOXE1} gene in the genetic susceptibility to TC and we reported its down expression among PTC tissues.
authors: Laboratoire de Microorganismes et Biomolécules, équipe des Procédés de Criblage Moléculaires et Cellulaires, Centre de Biotechnologie de Sfax, Tunisie.
authors: Rihab
authors: R
authors: Kallel
authors: Salima
authors: S
authors: Belguith-Maalej
authors: Abdelmounaim
authors: A
authors: Akdi
authors: Mouna
authors: M
authors: Mnif
authors: Ilhem
authors: I
authors: Charfeddine
authors: Pere
authors: P
authors: Galofré
authors: Abdelmonaim
authors: A
authors: Ghorbel
authors: Mohamed
authors: M
authors: Abid
authors: Ricard
authors: R
authors: Marcos
authors: Hammadi
authors: H
authors: Ayadi
authors: Antonia
authors: A
authors: Velázquez
authors: Hassen
authors: H
authors: Hadj Kacem
mesh_terms: D000328:Adult; D002277:Carcinoma / Q000235:genetics*; D005260:Female; D051858:Forkhead Transcription Factors / Q000235:genetics*; D020022:Genetic Predisposition to Disease; D006111:Graves Disease / Q000235:genetics; D050031:Hashimoto Disease / Q000235:genetics; D006801:Humans; D008297:Male; D008875:Middle Aged; D009230:Myxedema / Q000235:genetics; D010455:Peptides / Q000235:genetics*; D013964:Thyroid Neoplasms / Q000235:genetics*; D014416:Tunisia
chemical_list: C106894:FOXE1 protein, human; D051858:Forkhead Transcription Factors; D010455:Peptides; C019529:polyalanine