title: Comparison of Three BRAF Mutation Tests in Formalin-Fixed Paraffin Embedded Clinical Samples.
abstract: BACKGROUND
  Recently, BRAF inhibitors showed dramatic treatment outcomes in BRAF V600 mutant melanoma. Therefore, the accuracy of BRAF mutation test is critical.
  
  
  METHODS
  BRAF mutations were tested by dual-priming oligonucleotide-polymerase chain reaction (DPO-PCR), direct sequencing and subsequently retested with a real-time PCR assay, cobas 4800 V600 mutation test. In total, 64 tumors including 34 malignant melanomas and 16 papillary thyroid carcinomas were analyzed. DNA was extracted from formalin-fixed paraffin embedded tissue samples and the results of cobas test were directly compared with those of DPO-PCR and direct sequencing.
  
  
  RESULTS
  BRAF mutations were found in 23 of 64 (35.9%) tumors. There was 9.4% discordance among 3 methods. Out of 6 discordant cases, 4 cases were melanomas; 3 cases were BRAF V600E detected only by cobas test, but were not detected by DPO-PCR and direct sequencing. One melanoma patient with BRAF mutation detected only by cobas test has been on vemurafenib treatment for 6 months and showed a dramatic response to vemurafenib. DPO-PCR failed to detect V600K mutation in one case identified by both direct sequencing and cobas test.
  
  
  CONCLUSIONS
  In direct comparison of the currently available DPO-PCR, direct sequencing and real-time cobas test for BRAF mutation, real-time PCR assay is the most sensitive method.
authors.affiliation: Department of Pathology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Soomin
authors.initials: S
authors.lastname: Ahn
authors.forename: Jeeyun
authors.initials: J
authors.lastname: Lee
authors.forename: Ji-Youn
authors.initials: JY
authors.lastname: Sung
authors.forename: So Young
authors.initials: SY
authors.lastname: Kang
authors.forename: Sang Yun
authors.initials: SY
authors.lastname: Ha
authors.forename: Kee-Taek
authors.initials: KT
authors.lastname: Jang
authors.forename: Yoon-La
authors.initials: YL
authors.lastname: Choi
authors.forename: Jung-Sun
authors.initials: JS
authors.lastname: Kim
authors.forename: Young Lyun
authors.initials: YL
authors.lastname: Oh
authors.forename: Kyoung-Mee
authors.initials: KM
authors.lastname: Kim
keywords: BRAF mutation; Dual-priming oligonucleotide-PCR; Melanoma; Real-time polymerase chain reaction; Sanger sequencing