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BioMed Research International
Volume 2015, Article ID 697068, 8 pages
http://dx.doi.org/10.1155/2015/697068
Research Article

Preoperative RAS Mutational Analysis Is of Great Value in Predicting Follicular Variant of Papillary Thyroid Carcinoma

1Department of Pathology, Konkuk University School of Medicine, 120 Neungdong-ro, Hwayang-dong, Gwangjin-gu, Seoul 143-701, Republic of Korea
2Department of Surgery, Konkuk University School of Medicine, 120 Neungdong-ro, Hwayang-dong, Gwangjin-gu, Seoul 143-701, Republic of Korea
3Department of Pathology, Konkuk University Medical Center, 120-1 Neungdong-ro, Hwayang-dong, Gwangjin-gu, Seoul 143-729, Republic of Korea
4Department of Internal Medicine, Konkuk University School of Medicine, 120 Neungdong-ro, Hwayang-dong, Gwangjin-gu, Seoul 143-701, Republic of Korea

Received 8 August 2014; Accepted 11 October 2014

Academic Editor: George Pentheroudakis

Copyright © 2015 Tae Sook Hwang et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Follicular variant of papillary thyroid carcinoma (FVPTC), particularly the encapsulated subtype, often causes a diagnostic dilemma. We reconfirmed the molecular profiles in a large number of FVPTCs and investigated the efficacy of the preoperative mutational analysis in indeterminate thyroid nodules. BRAF V600E/K601E and RAS mutational analysis was performed on 187 FVPTCs. Of these, 132 (70.6%) had a point mutation in one of the BRAF V600E (), BRAF K601E (), or RAS () genes. All mutations were mutually exclusive. The most common RAS mutations were at NRAS codon 61. FNA aspirates from 564 indeterminate nodules were prospectively tested for BRAF and RAS mutation and the surgical outcome was correlated with the mutational status. Fifty-seven and 47 cases were positive for BRAF and RAS mutation, respectively. Twenty-seven RAS-positive patients underwent surgery and all except one patient had FVPTC. The PPV and accuracy of RAS mutational analysis for predicting FVPTC were 96% and 84%, respectively. BRAF or RAS mutations were present in more than two-thirds of FVPTCs and these were mutually exclusive. BRAF mutational analysis followed by N, H, and KRAS codon 61 mutational analysis in indeterminate thyroid nodules would streamline the management of patients with malignancies, mostly FVPTC.