title: Canadian anaplastic lymphoma kinase study: a model for multicenter standardization and optimization of ALK testing in lung cancer.
abstract: BACKGROUND
  Fluorescence in situ hybridization (FISH) is currently the standard for diagnosing anaplastic lymphoma kinase (ALK)-rearranged (ALK+) lung cancers for ALK inhibitor therapies. ALK immunohistochemistry (IHC) may serve as a screening and alternative diagnostic method. The Canadian ALK (CALK) study was initiated to implement a multicenter optimization and standardization of laboratory developed ALK IHC and FISH tests across 14 hospitals.
  
  
  METHODS
  Twenty-eight lung adenocarcinomas with known ALK status were used as blinded study samples. Thirteen laboratories performed IHC using locally developed staining protocols for 5A4, ALK1, or D5F3 antibodies; results were assessed by H-score. Twelve centers conducted FISH using protocols based on Vysis' ALK break-apart FISH kit. Initial IHC results were used to optimize local IHC protocols, followed by a repeat IHC study to assess the results of standardization. Three laboratories conducted a prospective parallel IHC and FISH analysis on 411 consecutive clinical samples using post-validation optimized assays.
  
  
  RESULTS
  Among study samples, FISH demonstrated 22 consensus ALK+ and six ALK wild type tumors. Preoptimization IHC scores from 12 centers with 5A4 and the percent abnormal cells by FISH from 12 centers showed intraclass correlation coefficients of 0.83 and 0.68, respectively. IHC optimization improved the intraclass correlation coefficients to 0.94. Factors affecting FISH scoring and outliers were identified. Post-optimization concurrent IHC/FISH testing in 373 informative cases revealed 100% sensitivity and specificity for IHC versus FISH.
  
  
  CONCLUSIONS
  Multicenter standardization study may accelerate the implementation of ALK testing protocols across a country/region. Our data support the use of an appropriately validated IHC assay to screen for ALK+ lung cancers.
authors.affiliation: *Department of Pathology and Molecular Medicine, McMaster University Health Sciences Centre and McMaster University, Hamilton, Ontario; †Department of Pathology, University Health Network, Princess Margaret Cancer Centre and University of Toronto, Toronto, Ontario; ‡Department of Pathology, Jewish General Hospital and Lady David Institute, McGill University, Montreal, Québec; §Cross Cancer Institute and Department of Laboratory Medicine & Pathology, University of Alberta, Edmonton, Alberta; ‖Department of Molecular Pathology, University of Alberta Hospital, Edmonton, Alberta; ¶Department of Pathology, Queen Elizabeth II Health Sciences Centre and Dalhousie University, Halifax, Nova Scotia; #Department of Pathology, Aichi Cancer Center Hospital, Nagoya, Japan; **Department of Pathology, British Columbia Cancer Agency and University of British Columbia, Vancouver, British Columbia; ††Department of Pathology, McGill University Health Centre, Montreal, Québec; ‡‡Department of Human Genetics, McGill University, Montreal, Québec; §§Department of Pathology, Health Sciences North, Sudbury, Ontario; ‖‖Department of Pathology and Laboratory Medicine, University of Calgary, Calgary, Alberta; ¶¶Department of Pathology, The Ottawa Hospital and University of Ottawa, Ottawa, Ontario; ##Centre hospitalier de l'Universite de Montreal, Montreal, Québec; ***Department of Pathology, London Health Sciences Centre, London, Ontario; †††Department of Molecular Genetics, University of Toronto, Toronto, Ontario; ‡‡‡Department of Pathology, Harvard Medical School, Massachusetts General Hospital, Boston, MA; §§§Pfizer Oncology Canada, Kirkland, Québec; and ‖‖‖Institut Universitaire de Cardiologie et de Pneumologie de Québec (Hôpital Laval), Université Laval, Québec, Québec.
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mesh_terms: D000230:Adenocarcinoma / Q000175:diagnosis / Q000201:enzymology* / Q000235:genetics; D000077192:Adenocarcinoma of Lung; D000077548:Anaplastic Lymphoma Kinase; D002170:Canada; D004273:DNA, Neoplasm / Q000235:genetics; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007150:Immunohistochemistry; D017404:In Situ Hybridization, Fluorescence / Q000379:methods; D008175:Lung Neoplasms / Q000175:diagnosis / Q000201:enzymology* / Q000235:genetics; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D020794:Receptor Protein-Tyrosine Kinases / Q000235:genetics / Q000378:metabolism*; D015203:Reproducibility of Results; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D004273:DNA, Neoplasm; C000626173:ALK protein, human; D000077548:Anaplastic Lymphoma Kinase; D020794:Receptor Protein-Tyrosine Kinases