title: Analysis of BRAF(V600E) mutation and DNA methylation improves the diagnostics of thyroid fine needle aspiration biopsies.
abstract: BACKGROUND
  Thyroid nodules with indeterminate cytological features on fine needle aspiration biopsy specimens (FNABs) have a ~20% risk of thyroid cancer. BRAF(V600E) mutation and DNA methylation are useful markers to distinguish malignant thyroid neoplasm from benign. The aim of this study was to determine whether combined detection of BRAF(V600E) mutation and methylation markers on FNABs could improve the diagnostic accuracy of thyroid cancer.
  
  
  METHODS
  Using pyrosequencing and quantitative methylation-specific PCR (Q-MSP) methods, FNABs from 79 and 38 patients with thyroid nodules in training and test groups, respectively, were analyzed for BRAF(V600E) mutation and gene methylation.
  
  
  RESULTS
  BRAF(V600E) mutation was found in 30/42 (71.4%) and 14/20 (70%) FNABs in training and test groups, respectively. All BRAF(V600E)-positive samples were histologically diagnosed as papillary thyroid cancer (PTC) after thyroidectomy. As expected, BRAF mutation was not found in all benign nodules. Moreover, we demonstrated that the five genes, including CALCA, DAPK1, TIMP3, RAR-beta and RASSF1A, were aberrantly methylated in FNABs. Of them, methylation level of DAPK1 in PTCs was significantly higher than that in benign samples (P <0.0001). Conversely, methylation level of RASSF1A in PTCs was significantly lower than that in benign samples (P =0.003). Notably, compared with BRAF mutation testing alone, combined detection of BRAF mutation and methylation markers increased the diagnostic sensitivity and accuracy of PTC with excellent specificity.
  
  
  CONCLUSIONS
  Our data have demonstrated that combine analysis of BRAF mutation and DNA methylation markers on FNABs may be a useful strategy to facilitate the diagnosis of malignant thyroid neoplasm, particularly PTC.
  The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/6080878071149177.
authors.forename: Bingfei
authors.initials: B
authors.lastname: Zhang
authors.forename: Shu
authors.initials: S
authors.lastname: Liu
authors.forename: Zhaoxia
authors.initials: Z
authors.lastname: Zhang
authors.forename: Jing
authors.initials: J
authors.lastname: Wei
authors.forename: Yiping
authors.initials: Y
authors.lastname: Qu
authors.forename: Kexia
authors.initials: K
authors.lastname: Wu
authors.forename: Qi
authors.initials: Q
authors.lastname: Yang
authors.affiliation: Department of Endocrinology, The First Affiliated Hospital of Xi'an Jiaotong University School of Medicine, Xi'an 710061, P, R, China. phou@mail.xjtu.edu.cn.
authors.forename: Peng
authors.initials: P
authors.lastname: Hou
authors.forename: Bingyin
authors.initials: B
authors.lastname: Shi
mesh_terms: D000328:Adult; D014408:Biomarkers, Tumor / Q000235:genetics*; D044963:Biopsy, Fine-Needle; D002277:Carcinoma; D002291:Carcinoma, Papillary; D019175:DNA Methylation; D004252:DNA Mutational Analysis / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D016133:Polymerase Chain Reaction; D048493:Proto-Oncogene Proteins B-raf / Q000235:genetics*; D000077273:Thyroid Cancer, Papillary; D013964:Thyroid Neoplasms; D016606:Thyroid Nodule / Q000175:diagnosis* / Q000235:genetics*
chemical_list: D014408:Biomarkers, Tumor; C482119:BRAF protein, human; D048493:Proto-Oncogene Proteins B-raf