Diagnosis of Papillary Thyroid Cancer via Detection of BRAF Mutation on Fine Needle Aspiration Cytology Slides / 대한내분비외과학회지

ABSTRACT

PURPOSE: The prevalence rate of the BRAF mutation in papillary thyroid cancer (PTC) is as high as about 52 to 83% in Korea. Preoperative detection of BRAF mutation on fine needle aspiration cytology (FNAC) slides may help the surgeon make better therapeutic decisions. The present study aims to assess the feasibility of the mutant allele specific amplification (MASA) and restriction fragment length polymorphism (RFLP) method with using conventional FNAC slides and we also wanted to evaluate the clinical role of preoperatively detecting BRAF mutation. METHODS: We extracted the genomic DNA from 59 FNAC slides and performed direct sequencing (DS) for detecting BRAF mutation. We could use only 17 slides for the MASA method and 6 slides for the RFLP method due to the shortage of extracted DNA. Additionally, we retrospectively analyzed the cases for which a histological diagnosis could be made. RESULTS: Genomic DNA was extracted from 23 out of the 59 FNAC slides. The BRAF mutation status could be assessed via DS in 33 out of the 59 FNAC slides. The concordance between the MASA method and DS and the RFLP method and DS was 36.3% and 66.7% respectively. The positive and negative predictive value of the 13 indeterminate nodules was 87.5% and 20%, respectively. We could not find any association between the BRAF mutations and the alleged risk factors of PTC. CONCLUSION: We believe that the purity and the amount of the DNA template must be increased to detect BRAF mutation with using a FNAC slide. Preoperative detection of the BRAF mutation on a FNAC slide may refine the cytological diagnosis, but the application of assessing BRAF mutation as a prognostic marker is debatable.