title: Immunohistochemical detection of NRAS(Q61R) protein in follicular-patterned thyroid tumors.
abstract: The NRAS(A182G) mutation, which results in the NRAS(Q61R) protein, is a major driver mutation in follicular-patterned thyroid neoplasms. Although new immunohistochemistry (IHC) for NRAS(Q61R) is now available, its sensitivity, specificity, and diagnostic utility for thyroid tumors are not yet established. We performed IHC for NRAS(Q61R) and direct sequencing for NRAS codon 61 in 4 thyroid cancer-derived cell lines and 98 follicular-patterned thyroid tumors that included 22 follicular thyroid adenomas (FTAs), 35 follicular thyroid carcinomas (FTCs), and 41 cases of nodular hyperplasia (NH). In the tumors with NRAS(Q61R), the expression of BRAF(V600E) was further evaluated immunohistochemically. Two cell lines with NRAS(A182G) showed selective immunoreactivity for NRAS(Q61R). In tumor tissues, NRAS(Q61R) IHC was positive in 18% (4/22), 29% (10/35), and 2% (1/41) of FTAs, FTCs, and NH samples, respectively. The frequencies of the NRAS(Q61R) in FTAs and FTCs were significantly higher than that in NH (P=.046 and P=.001, respectively). All tumors with NRAS(Q61R) expression exhibited uniform cytoplasmic positivity with or without accumulation in their cell membranes. Of the 15 tumors with NRAS(Q61R) expression, 13 cases showed NRAS(A182G) in direct sequencing, whereas all of the tumors without NRAS(Q61R) expression were negative for the mutation. There were no tumors with overlapping expression of NRAS(Q61R) and BRAF(V600E). In reference to the direct sequencing, sensitivity and specificity of the NRAS(Q61R) IHC were 100% and 98%, respectively. In conclusion, NRAS(Q61R) IHC is a highly sensitive and specific tool that is useful for differentiating follicular-patterned thyroid tumors.
authors.affiliation: Department of Pathology, University of Yamanashi, Chuo, Yamanashi 409-3898, Japan.
authors.forename: Naoki
authors.initials: N
authors.lastname: Oishi
authors.affiliation: Department of Pathology, University of Yamanashi, Chuo, Yamanashi 409-3898, Japan.
authors.forename: Tetsuo
authors.initials: T
authors.lastname: Kondo
authors.affiliation: Department of Pathology, University of Yamanashi, Chuo, Yamanashi 409-3898, Japan.
authors.forename: Huy Gia
authors.initials: HG
authors.lastname: Vuong
authors.affiliation: Department of Pathology, University of Yamanashi, Chuo, Yamanashi 409-3898, Japan.
authors.forename: Tadao
authors.initials: T
authors.lastname: Nakazawa
authors.affiliation: Department of Pathology, University of Yamanashi, Chuo, Yamanashi 409-3898, Japan.
authors.forename: Kunio
authors.initials: K
authors.lastname: Mochizuki
authors.affiliation: Department of Pathology, University of Yamanashi, Chuo, Yamanashi 409-3898, Japan.
authors.forename: Kazunari
authors.initials: K
authors.lastname: Kasai
authors.affiliation: Department of Pathology, University of Yamanashi, Chuo, Yamanashi 409-3898, Japan.
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Inoue
authors.affiliation: Department of Pathology, University of Yamanashi, Chuo, Yamanashi 409-3898, Japan.
authors.forename: Ippei
authors.initials: I
authors.lastname: Tahara
authors.affiliation: Department of Diagnostic Pathology, Kuma Hospital, Kobe, Hyogo, 650-0011, Japan.
authors.forename: Mitsuyoshi
authors.initials: M
authors.lastname: Hirokawa
authors.affiliation: Department of Surgery, Kuma Hospital, Kobe, Hyogo, 650-0011, Japan.
authors.forename: Akira
authors.initials: A
authors.lastname: Miyauchi
authors.affiliation: Department of Pathology, University of Yamanashi, Chuo, Yamanashi 409-3898, Japan. Electronic address: rkatoh@yamanashi.ac.jp.
authors.forename: Ryohei
authors.initials: R
authors.lastname: Katoh
mesh_terms: D018263:Adenocarcinoma, Follicular / Q000737:chemistry* / Q000235:genetics / Q000473:pathology; D014408:Biomarkers, Tumor / Q000032:analysis* / Q000235:genetics; D001706:Biopsy; D045744:Cell Line, Tumor; D004252:DNA Mutational Analysis; D003937:Diagnosis, Differential; D020558:GTP Phosphohydrolases / Q000032:analysis* / Q000235:genetics; D006801:Humans; D007150:Immunohistochemistry; D008565:Membrane Proteins / Q000032:analysis* / Q000235:genetics; D009154:Mutation; D011237:Predictive Value of Tests; D011379:Prognosis; D015203:Reproducibility of Results
chemical_list: D014408:Biomarkers, Tumor; D008565:Membrane Proteins; D020558:GTP Phosphohydrolases; C579846:NRAS protein, human
keywords: Follicular adenoma; Follicular carcinoma; Immunohistochemistry; Mutation; NRAS(Q61R); Thyroid