title: Intermediate microRNA expression profile in Graves' disease falls between that of normal thyroid tissue and papillary thyroid carcinoma.
abstract: OBJECTIVE
  Many studies have previously reported a higher prevalence of papillary thyroid carcinomas (PTC) in patients with Graves' disease (GD). MicroRNAs (miRNAs) are small, non-coding RNAs that are upregulated in PTC compared with benign thyroid tissue. The objective of the study was to examine the miRNA expression of selected miRNAs that are known to be upregulated in PTC in patients with GD.
  
  
  METHODS
  Paraffin embedded thyroid tissue from 159 patients with GD was screened for expression of the miRNAs 146b, 181b, 21, 221 and 222 by RT-PCR. The expression profiles of four normal thyroids, 50 PTCs without concomitant GD and 11 patients with untreated GD served as the controls.
  
  
  RESULTS
  The expression pattern of these miRNAs in patients with GD is intermediate between that of benign thyroid tissue (p<0.001) and PTC (in three out of five miRNAs, p<0.001). This corresponds to a 15-fold change for GD versus PTC, and a 31-fold change for GD versus normal thyroid tissue. The miRNA expression in 11 papillary microcarcinomas found in our study (a prevalence of 0.07) was not different from that in PTC samples from patients without GD for four of five miRNA types. Furthermore, we found a significant difference in the expression of miRNA 221/222 between treated and untreated GD tissue.
  
  
  CONCLUSIONS
  In conclusion, we found an intermediate expression of specific miRNAs in thyroid tissue from patients with GD that fell between the expression levels found in normal thyroid glands and PTC, which suggests a possible influence of certain miRNAs on developing PTC in patients with GD.
authors.affiliation: Institute of Pathology and Neuropathology, University Hospital of Essen, University of Duisburg-Essen, Essen, Germany.
authors.forename: Matthias
authors.initials: M
authors.lastname: Pohl
authors.affiliation: Institute of Pathology and Neuropathology, University Hospital of Essen, University of Duisburg-Essen, Essen, Germany.
authors.forename: Florian
authors.initials: F
authors.lastname: Grabellus
authors.affiliation: Institute of Pathology and Neuropathology, University Hospital of Essen, University of Duisburg-Essen, Essen, Germany.
authors.forename: Karl
authors.initials: K
authors.lastname: Worm
authors.affiliation: Center of Pathology Essen-Mitte, Essen, Germany.
authors.forename: Georg
authors.initials: G
authors.lastname: Arnold
authors.affiliation: Department of Surgery, Center of Minimally Invasive Surgery, Kliniken Essen-Mitte, Essen, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Walz
authors.affiliation: Institute of Pathology and Neuropathology, University Hospital of Essen, University of Duisburg-Essen, Essen, Germany.|Member of the West German Cancer Centre Essen (WTZE), Essen, Germany.
authors.forename: Kurt Werner
authors.initials: KW
authors.lastname: Schmid
authors.affiliation: Institute of Pathology and Neuropathology, University Hospital of Essen, University of Duisburg-Essen, Essen, Germany.|Institute of Pathology Recklinghausen, Recklinghausen, Germany.
authors.forename: Sien-Yi
authors.initials: SY
authors.lastname: Sheu-Grabellus
mesh_terms: D000328:Adult; D002291:Carcinoma, Papillary / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D015972:Gene Expression Regulation, Neoplastic; D006111:Graves Disease / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D006801:Humans; D008297:Male; D035683:MicroRNAs / Q000235:genetics / Q000378:metabolism*; D013961:Thyroid Gland / Q000378:metabolism* / Q000473:pathology; D013964:Thyroid Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology
chemical_list: D035683:MicroRNAs
keywords: HISTOPATHOLOGY; MOLECULAR PATHOLOGY; THYROID CANCER