BRAF mutation in cytologically indeterminate thyroid nodules: after reclassification of a variant thyroid carcinoma

Fine-needle aspiration biopsy (FNAB) is regarded by the Bethesda system as the gold-standard investigation for stratifying the risk of malignancy of a thyroid nodule. However, some limitations affect the adequacy of the obtained materials, resulting in 30% of the cytological results remaining in the...

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Bibliographic Details
Published in:OncoTargets and therapy 2019-01, Vol.12, p.1465-1473
Main Authors: Pongsapich, Warut, Chongkolwatana, Cheerasook, Poungvarin, Naravat, Amornpichetkul, Kanchana, Piyawattayakorn, Nutthaya, Vejvisithsakul, Pichpisith, Maneeprasopchoke, Prachya
Format: Article
Language:English
Subjects:
Biopsy
Cancer
Carcinoma
Cellular biology
Deoxyribonucleic acid
Diagnosis
DNA
DNA sequencing
Gene mutations
Genetic aspects
Genetic testing
Histopathology
Hospitals
Immunohistochemistry
Kinases
Laboratories
Medical prognosis
Medical research
Medicine
Medicine, Experimental
Mutation
Nucleotide sequencing
Original Research
Otolaryngology
Systematic review
Thyroid cancer
Thyroid diseases
Tumors
Ultrasonic imaging
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Summary:Fine-needle aspiration biopsy (FNAB) is regarded by the Bethesda system as the gold-standard investigation for stratifying the risk of malignancy of a thyroid nodule. However, some limitations affect the adequacy of the obtained materials, resulting in 30% of the cytological results remaining in the indeterminate category. We aimed to investigate the diagnostic value of the BRAF mutation in cytologically indeterminate thyroid nodules after the reclassification of a variant thyroid carcinoma. In this prospective diagnostic study, 76 patients with FNAB findings of atypia of undetermined significance (AUS) and suspicious for malignancy (SUS) were included. The BRAF V600 mutation from FNAB was confirmed by a PCR-based method (Sanger sequencing combined with allele-specific real-time PCR techniques) and immunohistochemistry (IHC). Pathological specimens and features, including noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP), were reviewed and compared to the FNAB results. Using the PCR-based method, the BRAF mutation was positive in 13/76 cases (17.1%), with the diagnostic values of 16.7% sensitivity, 100% specificity, 100% positive predictive value (PPV), and 82.8% negative predictive value (NPV) in the AUS compared to 73.3% sensitivity, 100% specificity, 100% PPV, and 20% NPV in the SUS. For the IHC technique, only 20 of the 76 cytological specimens were qualified for testing. The BRAF mutation was positive in 13/20 cases, with the diagnostic values of 100% sensitivity, 63.6% specificity, 42.9% PPV, and 100% NPV in the AUS compared to 100% sensitivity and PPV in the SUS. The BRAF mutation was not found in the pathological reports for NIFTP. The malignancy rate is high in our data, with specific and acceptable accuracy rates for the BRAF mutation from FNAB found by using the PCR-based method. NIFTP has been introduced after the pathological reclassification. Molecular diagnosis might be useful to establish the nature of the disease.
ISSN:1178-6930
1178-6930
DOI:10.2147/OTT.S190001