title: Detection of RAS mutation by pyrosequencing in thyroid cytology samples.
abstract: BACKGROUND
  Fine-needle aspiration cytology (FNAC) is the primary means to distinguish benign from malignant thyroid nodules. However, adjunctive diagnostic tests are needed as 20-40% of FNAC are inconclusive. RAS mutations have been described in differentiated thyroid cancer and they could be used as tumor markers. However, their prevalence varies widely among studies, probably as a result of the detection methods used. We investigated whether the pyrosequencing method can be applied to detect NRAS and KRAS mutations in thyroid aspirates.
  
  
  METHODS
  A total of 37 thyroid aspirates, including benign hyperplastic nodules (HBN, N = 16) and follicular thyroid carcinomas (FTC, N = 21) were analyzed for the presence of NRAS(61) and KRAS(13) mutations.
  
  
  RESULTS
  A RAS mutation was found in 31% and 62% of BN and FTC respectively. Most samples displayed a percentage of mutated alleles lower than 50% (median = 30.8% and 15.3% in FTC and HBN respectively), a result compatible with the presence of extra-nodular cells contaminating the FNA or with the subclonal nature of both types of thyroid nodules.
  
  
  CONCLUSIONS
  Pyrosequencing is a reliable assay to detect RAS mutations in fine-needle thyroid aspirates.
  
  
  CONCLUSIONS
  The low specificity and sensitivity limit the power of this test to distinguish between FTC and benign nodules in inconclusive FNACs.
authors.affiliation: Department of Medicine and Surgery, University of Salerno, Via Allende, 84081 Baronissi, Salerno, Italy.
authors.forename: Anna
authors.initials: A
authors.lastname: Guerra
authors.affiliation: S.C. Endocrinologia, AOU San Giovanni di Dio e Ruggi d'Aragona, Salerno, Italy.
authors.forename: Mario
authors.initials: M
authors.lastname: Carrano
authors.affiliation: S.C. Endocrinologia, AOU San Giovanni di Dio e Ruggi d'Aragona, Salerno, Italy.
authors.forename: Elisabetta
authors.initials: E
authors.lastname: Angrisani
authors.affiliation: Department of Medicine and Surgery, University of Salerno, Via Allende, 84081 Baronissi, Salerno, Italy.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Puzziello
authors.affiliation: Department of Medicine and Surgery, University of Salerno, Via Allende, 84081 Baronissi, Salerno, Italy.
authors.forename: Giulia
authors.initials: G
authors.lastname: Izzo
authors.affiliation: Department of Medicine and Surgery, University of Salerno, Via Allende, 84081 Baronissi, Salerno, Italy.
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Di Crescenzo
authors.affiliation: Department of Medicine and Surgery, University of Salerno, Via Allende, 84081 Baronissi, Salerno, Italy.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Vatrella
authors.affiliation: Department of Medicine and Surgery, University of Salerno, Via Allende, 84081 Baronissi, Salerno, Italy. Electronic address: mavitale@unisa.it.
authors.forename: Mario
authors.initials: M
authors.lastname: Vitale
mesh_terms: D018263:Adenocarcinoma, Follicular / Q000235:genetics* / Q000473:pathology; D000328:Adult; D014408:Biomarkers, Tumor / Q000235:genetics*; D044963:Biopsy, Fine-Needle; D005260:Female; D020558:GTP Phosphohydrolases / Q000235:genetics*; D006801:Humans; D008297:Male; D008565:Membrane Proteins / Q000235:genetics*; D008875:Middle Aged; D009154:Mutation; D011518:Proto-Oncogene Proteins / Q000235:genetics*; D016283:Proto-Oncogene Proteins p21(ras); D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D017422:Sequence Analysis, DNA / Q000379:methods*; D013964:Thyroid Neoplasms / Q000235:genetics* / Q000473:pathology; D016606:Thyroid Nodule / Q000235:genetics / Q000473:pathology; D018631:ras Proteins / Q000235:genetics*
chemical_list: D014408:Biomarkers, Tumor; C117307:KRAS protein, human; D008565:Membrane Proteins; D011518:Proto-Oncogene Proteins; D020558:GTP Phosphohydrolases; C579846:NRAS protein, human; D016283:Proto-Oncogene Proteins p21(ras); D018631:ras Proteins
keywords: FNAC; RAS; Thyroid carcinoma