title: Evaluating the effectiveness of RNA in-situ hybridization for detecting lung adenocarcinoma with anaplastic lymphoma kinase rearrangement.
abstract: OBJECTIVE
  An easy and rapid assay for detecting mRNA in formalin-fixed paraffin-embedded samples [RNA in-situ hybridization (ISH)] has been reported recently. The aim of this study was to investigate the diagnostic accuracy of RNA ISH in detecting lung adenocarcinoma (LA) with anaplastic lymphoma kinase (ALK) gene rearrangement.
  
  
  RESULTS
  We tested ALK RNA ISH on 11 resected LAs for which ALK fusion was confirmed by immunohistochemistry (IHC) and/or fluorescence in-situ hybridization (FISH). ALK mRNA expression was detected by RNA ISH in all 11 ALK-positive LAs, with a mean positive cell proportion of 68.4% (median, 75.3%; range, 3-98.8%), by counting 100 tumour cells at 10 different loci; RNA ISH did not detect ALK mRNA expression in the normal surrounding lung cells. Next, we explored the concordance between ALK RNA ISH and IHC/FISH tests by using tissue microarrays (TMAs) containing 294 LAs. In the TMA slides, we found five ALK-positive cases with IHC and/or FISH. The mean proportion of ALK RNA ISH-positive cells in these five cases was 75.6% (median, 82%; range, 40-94%), whereas the proportion of ALK RNA ISH-positive cells in the remaining 289 cases was 0.3% (median 0%; range, 0-15%). When the cutoff value was set at 15%, ALK RNA ISH-positive and ALK RNA ISH-negative cases were distinguishable with 100% sensitivity and specificity relative to the IHC/FISH tests.
  
  
  CONCLUSIONS
  Our findings show that RNA ISH is useful for detecting ALK rearrangement with high sensitivity and specificity relative to conventional IHC/FISH tests. Thus, RNA ISH, which is an easy and rapid assay, could be an alternative method to IHC and FISH.
authors.affiliation: Department of Diagnostic Pathology, Kyoto University Hospital, Kyoto, Japan.
authors.forename: Naoki
authors.initials: N
authors.lastname: Nakajima
authors.affiliation: Department of Diagnostic Pathology, Kyoto University Hospital, Kyoto, Japan.
authors.forename: Akihiko
authors.identifier: http://orcid.org/0000-0003-1462-7341
authors.initials: A
authors.lastname: Yoshizawa
authors.affiliation: Department of Diagnostic Pathology, Kyoto University Hospital, Kyoto, Japan.
authors.forename: Kyoko
authors.initials: K
authors.lastname: Kondo
authors.affiliation: Department of Diagnostic Pathology, Kyoto University Hospital, Kyoto, Japan.
authors.forename: Mariyo
authors.initials: M
authors.lastname: Rokutan-Kurata
authors.affiliation: Department of Diagnostic Pathology, Kyoto University Hospital, Kyoto, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Hirata
authors.affiliation: Department of Diagnostic Pathology, Kyoto University Hospital, Kyoto, Japan.
authors.forename: Ayako
authors.initials: A
authors.lastname: Furuhata
authors.affiliation: Department of Diagnostic Pathology, Kyoto University Hospital, Kyoto, Japan.|Department of Diagnostic Pathology, Kumamoto University Hospital, Kumamoto, Japan.
authors.forename: Shinji
authors.initials: S
authors.lastname: Sumiyoshi
authors.affiliation: Department of Thoracic Surgery, Kyoto University Hospital, Kyoto, Japan.
authors.forename: Makoto
authors.initials: M
authors.lastname: Sonobe
authors.affiliation: Department of Thoracic Surgery, Kyoto University Hospital, Kyoto, Japan.
authors.forename: Toshi
authors.initials: T
authors.lastname: Menju
authors.affiliation: Department of Laboratory Medicine, Shinshu University Hospital, Matsumoto, Japan.
authors.forename: Masanobu
authors.initials: M
authors.lastname: Momose
authors.affiliation: Department of Diagnostic Pathology, Kyoto University Hospital, Kyoto, Japan.|Diagnostic Pathology, Wakayama Medical University Hospital, Wakayama, Japan.
authors.forename: Masakazu
authors.initials: M
authors.lastname: Fujimoto
authors.affiliation: Department of Thoracic Surgery, Kyoto University Hospital, Kyoto, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Date
authors.affiliation: Department of Diagnostic Pathology, Kyoto University Hospital, Kyoto, Japan.
authors.forename: Hironori
authors.initials: H
authors.lastname: Haga
mesh_terms: D000230:Adenocarcinoma / Q000175:diagnosis* / Q000235:genetics; D000077192:Adenocarcinoma of Lung; D000077548:Anaplastic Lymphoma Kinase; D015321:Gene Rearrangement; D006801:Humans; D017404:In Situ Hybridization, Fluorescence / Q000379:methods*; D008175:Lung Neoplasms / Q000175:diagnosis* / Q000235:genetics; D012313:RNA / Q000032:analysis; D020794:Receptor Protein-Tyrosine Kinases / Q000235:genetics*; D012680:Sensitivity and Specificity
chemical_list: D012313:RNA; C000626173:ALK protein, human; D000077548:Anaplastic Lymphoma Kinase; D020794:Receptor Protein-Tyrosine Kinases
keywords: RNA in-situ hybridization; anaplastic lymphoma kinase gene rearrangement; fluorescence in-situ hybridization; immunohistochemistry; lung adenocarcinoma