title: Equivocal ALK fluorescence in-situ hybridization (FISH) cases may benefit from ancillary ALK FISH probe testing.
abstract: OBJECTIVE
  Accurate assessment of anaplastic lymphoma kinase (ALK) gene rearrangement in non-small-cell lung cancers (NSCLCs) is critical to identify patients who are likely to respond to crizotinib. The aim of this study was to evaluate the ALK/EML4 TriCheck FISH probe in a series of NSCLCs enriched for tumours with equivocal ALK status.
  
  
  RESULTS
  ALK FISH was prospectively performed on 45 NSCLCs with the ALK/EML4 TriCheck probe (ZytoVision) and the Vysis ALK break-apart probe (Abbott Molecular). ALK immunohistochemistry was performed with 5A4 and D5F3 antibodies. Fourteen cases had equivocal ALK status, based on borderline or focal FISH positivity, an atypical FISH pattern, or discrepancy between ALK FISH and immunohistochemistry. Four of the 14 equivocal cases showed discordance between the two FISH probes. All other cases were concordant. The TriCheck probe showed that, of 31 unequivocal cases, 15 were ALK-rearranged, and 60% of these had EML4 as the translocation partner. Within the group of 14 equivocal cases, 12 showed rearrangement with the Tricheck probe; only one of these showed EML4 rearrangement. Of the six equivocal cases that received crizotinib, four showed clinical benefit.
  
  
  CONCLUSIONS
  The ALK/EML4 TriCheck FISH probe may be useful for the detection of ALK rearrangements, especially in borderline or atypical cases, where an additional unique ALK FISH probe may provide further confirmation of rearrangement.
authors.affiliation: Tissue Pathology and Diagnostic Oncology, Royal Prince Alfred Hospital, Camperdown, NSW, Australia.
authors.forename: Christina
authors.initials: C
authors.lastname: Selinger
authors.affiliation: Tissue Pathology and Diagnostic Oncology, Royal Prince Alfred Hospital, Camperdown, NSW, Australia.|School of Medicine, University of Western Sydney, Campbelltown, NSW, Australia.|Sydney Medical School, University of Sydney, Sydney, NSW, Australia.
authors.forename: Wendy
authors.initials: W
authors.lastname: Cooper
authors.affiliation: Tissue Pathology and Diagnostic Oncology, Royal Prince Alfred Hospital, Camperdown, NSW, Australia.
authors.forename: Trina
authors.initials: T
authors.lastname: Lum
authors.affiliation: Chris O'Brien Lifehouse and Royal Prince Alfred Hospital, Camperdown, NSW, Australia.
authors.forename: Catriona
authors.initials: C
authors.lastname: McNeil
authors.affiliation: SydPath, Anatomical Pathology, St Vincent's Hospital, Darlinghurst, NSW, Australia.
authors.forename: Adrienne
authors.initials: A
authors.lastname: Morey
authors.affiliation: Department of Pathology, University of Melbourne, Melbourne, Vic., Australia.
authors.forename: Paul
authors.initials: P
authors.lastname: Waring
authors.affiliation: PathWest, Sir Charles Gairdner Hospital, Nedlands, WA, Australia.|School of Pathology and Laboratory Medicine, University of Western Australia, Nedlands, WA, Australia.
authors.forename: Benhur
authors.initials: B
authors.lastname: Amanuel
authors.affiliation: School of Medicine and Pharmacology, University of Western Australia, Nedlands, WA, Australia.|Department of Medical Oncology, Sir Charles Gairdner Hospital, Nedlands, WA, Australia.
authors.forename: Michael
authors.initials: M
authors.lastname: Millward
authors.affiliation: PathWest, Sir Charles Gairdner Hospital, Nedlands, WA, Australia.
authors.forename: Joanne
authors.initials: J
authors.lastname: Peverall
authors.affiliation: PathWest, Sir Charles Gairdner Hospital, Nedlands, WA, Australia.|School of Pathology and Laboratory Medicine, University of Western Australia, Nedlands, WA, Australia.
authors.forename: Chris
authors.initials: C
authors.lastname: Van Vliet
authors.affiliation: Department of Pathology, University of Melbourne, Melbourne, Vic., Australia.|Department of Anatomical Pathology and Medical Oncology, The Royal Melbourne Hospital, Parkville, Vic., Australia.
authors.forename: Michael
authors.initials: M
authors.lastname: Christie
authors.affiliation: Ballarat Base Hospital, Ballarat, Vic., Australia.
authors.forename: Yen
authors.initials: Y
authors.lastname: Tran
authors.affiliation: Royal North Shore Hospital, St Leonards, NSW, Australia.
authors.forename: Connie
authors.initials: C
authors.lastname: Diakos
authors.affiliation: Royal North Shore Hospital, St Leonards, NSW, Australia.
authors.forename: Nick
authors.initials: N
authors.lastname: Pavlakis
authors.affiliation: Sydney Medical School, University of Sydney, Sydney, NSW, Australia.|Royal North Shore Hospital, St Leonards, NSW, Australia.|Cancer Diagnosis and Pathology Research Group, Kolling Institute of Medical Research, St Leonards, NSW, Australia.
authors.forename: Anthony J
authors.initials: AJ
authors.lastname: Gill
authors.affiliation: Tissue Pathology and Diagnostic Oncology, Royal Prince Alfred Hospital, Camperdown, NSW, Australia.|The Kinghorn Cancer Centre, Garvan Institute of Medical Research, Darlinghurst, NSW, Australia.
authors.forename: Sandra
authors.initials: S
authors.lastname: O'Toole
mesh_terms: D000077548:Anaplastic Lymphoma Kinase; D002289:Carcinoma, Non-Small-Cell Lung / Q000235:genetics*; D015331:Cohort Studies; D015321:Gene Rearrangement; D006801:Humans; D007150:Immunohistochemistry; D017404:In Situ Hybridization, Fluorescence / Q000379:methods*; D008175:Lung Neoplasms / Q000235:genetics*; D020794:Receptor Protein-Tyrosine Kinases / Q000235:genetics*
chemical_list: C000626173:ALK protein, human; D000077548:Anaplastic Lymphoma Kinase; D020794:Receptor Protein-Tyrosine Kinases
keywords: anaplastic lymphoma kinase; fluorescence in-situ hybridization; lung adenocarcinoma; non-small-cell lung cancer