title: Impact of molecular screening for point mutations and rearrangements in routine air-dried fine-needle aspiration samples of thyroid nodules.
abstract: BACKGROUND
  The diagnostic limitations of thyroid fine-needle aspiration (FNA), such as the indeterminate category, can be partially overcome by molecular analyses. However, until now, rearrangements have only been detected in fresh FNA material and the number of follicular thyroid carcinomas (FTCs) was rather low in previous studies. We aimed at investigating the impact of point mutations and rearrangement detection in a set of routine air-dried FNA smears with a higher percentage of FTCs.
  
  
  METHODS
  RNA and DNA was extracted from 310 FNAs (164 indeterminate, 57 malignant, 89 benign) and corresponding formalin-fixed paraffin-embedded tissue (156 follicular adenomas [FAs], 32 FTCs, 44 papillary thyroid carcinomas [PTCs], 9 follicular variant PTCs, and 69 goiters). PAX8/PPARG and RET/PTC rearrangements were detected by qPCR, BRAF and RAS mutations by high-resolution melting PCR and by pyrosequencing.
  
  
  RESULTS
  Forty-seven mutations were detected in the FNAs: 22 BRAF, 13 NRAS, and 3 HRAS mutations, 8 PAX8/PPARG, and one RET/PTC-rearrangement. While the presence of a BRAF and RET/PTC mutation was associated with cancer in 100% of samples each, the presence of a RAS and PAX8/PPARG mutation was associated with cancer in only 12% and 50% of samples, respectively. In the indeterminate group 4 of 25 carcinomas were identified by molecular FNA screening, which increased the sensitivity from 67% (cytology alone) to 75% (cytology plus molecular screening).
  
  
  CONCLUSIONS
  Molecular screening for point mutations and rearrangements is feasible in air-dried FNAs. Although the impact of detecting point mutations and rearrangements in FNAs has most likely been overestimated in previous studies, molecular FNA analyses improve presurgical diagnostics. The detection of BRAF mutations in FNA may improve the choice of surgery and postsurgical treatment. Further data are necessary to elucidate the true impact of detecting RAS and PAX8/PPARG mutations in FNAs. The inclusion of additional rare somatic mutations and miRNA markers might further improve the impact of molecular FNA diagnostics.
authors.affiliation: 1 Division of Endocrinology and Nephrology, Statistics and Epidemiology (IMISE), Leipzig Research Center for Civilization Diseases (LIFE); University of Leipzig , Leipzig, Germany .
authors.forename: Markus
authors.initials: M
authors.lastname: Eszlinger
authors.forename: Annelise
authors.initials: A
authors.lastname: Krogdahl
authors.forename: Sina
authors.initials: S
authors.lastname: Münz
authors.forename: Christian
authors.initials: C
authors.lastname: Rehfeld
authors.forename: Eva Magrethe
authors.initials: EM
authors.lastname: Precht Jensen
authors.forename: Carolina
authors.initials: C
authors.lastname: Ferraz
authors.forename: Eileen
authors.initials: E
authors.lastname: Bösenberg
authors.forename: Norbert
authors.initials: N
authors.lastname: Drieschner
authors.forename: Markus
authors.initials: M
authors.lastname: Scholz
authors.forename: Laszlo
authors.initials: L
authors.lastname: Hegedüs
authors.forename: Ralf
authors.initials: R
authors.lastname: Paschke
mesh_terms: D044963:Biopsy, Fine-Needle; D015321:Gene Rearrangement; D006801:Humans; D025202:Molecular Diagnostic Techniques / Q000379:methods*; D000072636:PAX8 Transcription Factor; D047495:PPAR gamma / Q000235:genetics; D051761:Paired Box Transcription Factors / Q000235:genetics; D016612:Paraffin Embedding; D017354:Point Mutation; D048493:Proto-Oncogene Proteins B-raf / Q000235:genetics*; D051096:Proto-Oncogene Proteins c-ret / Q000235:genetics; D012189:Retrospective Studies; D013048:Specimen Handling / Q000379:methods; D016606:Thyroid Nodule / Q000473:pathology*; D018631:ras Proteins / Q000235:genetics*
chemical_list: D000072636:PAX8 Transcription Factor; C083325:PAX8 protein, human; D047495:PPAR gamma; D051761:Paired Box Transcription Factors; D051096:Proto-Oncogene Proteins c-ret; C099282:RET protein, human; D048493:Proto-Oncogene Proteins B-raf; D018631:ras Proteins