title: Immunohistochemistry is a reliable screening tool for identification of ALK rearrangement in non-small-cell lung carcinoma and is antibody dependent.
abstract: BACKGROUND
  Fluorescence in situ hybridization (FISH) is the standard procedure for the detection of anaplastic lymphoma receptor tyrosine kinase (ALK) rearrangement in non-small-cell lung carcinoma (NSCLC) but is expensive and time consuming. We tested three antibodies to ALK, using various detection systems, and hypothesized that ALK immunohistochemistry (IHC) may represent a cost-effective and efficient means of screening for ALK rearrangement in NSCLC.
  
  
  METHODS
  We screened 377 stage I or II NSCLC cases in a tissue microarray by FISH and IHC (5A4 [Leica Biosystems Newcastle Ltd, Newcastle upon Tyne, UYnited Kingdom] by Nichirei's N-Histofine ALK detection kit [Nichirei Biosciences inc., Tokyo, Japan], 5A4 by Novocastra with ADVANCE [Dako Canada inc., Burlington, Ontario, Canada], D5F3 by Cell Signaling Technology with ADVANCE [Cell Signalling Technologies inc., Danvers, MA], and DAKO clone ALK1 with FLEX [Dako Canada inc., Burlington, Ontario, Canada] and ADVANCE). IHC was scored as 0, 1+, 2+, or 3+. Possibly positive or positive cases were further analyzed by IHC and FISH on whole section.
  
  
  RESULTS
  Tissue microarray results were available on 377 cases by IHC and 273 cases by FISH. Eleven cases were positive or possibly positive by either IHC or FISH, and three cases were positive or possibly positive by both methods. Three cases were ALK-positive by FISH on whole section validation. There was no correlation between semiquantitative IHC score (1+, 2+, 3+) and ALK rearrangement by FISH. D5F3 (Cell Signaling by ADVANCE) and 5A4 (Novocastra by ADVANCE) showed the greatest combination of sensitivity (100%) and specificity (87.5% for 5A4 by Novocastra and 75% for D5F3 by Cell Signaling), and produced no false-negative results.
  
  
  CONCLUSIONS
  IHC is a reliable screening tool for identification of ALK rearrangement in NSCLC and is antibody dependent. D5F3 (Cell Signaling) and 5A4 (Novocastra) can be used with FISH for identification of IHC-positive cases to reduce screening costs.
authors.affiliation: University of British Columbia, Vancouver, British Columbia, Canada.
authors.forename: Chris M J
authors.initials: CM
authors.lastname: Conklin
authors.forename: Kenneth J
authors.initials: KJ
authors.lastname: Craddock
authors.forename: Cherry
authors.initials: C
authors.lastname: Have
authors.forename: Janessa
authors.initials: J
authors.lastname: Laskin
authors.forename: Christian
authors.initials: C
authors.lastname: Couture
authors.forename: Diana N
authors.initials: DN
authors.lastname: Ionescu
mesh_terms: D000230:Adenocarcinoma / Q000235:genetics; D000368:Aged; D000077548:Anaplastic Lymphoma Kinase; D000906:Antibodies; D018287:Carcinoma, Large Cell / Q000235:genetics; D002289:Carcinoma, Non-Small-Cell Lung / Q000235:genetics*; D002294:Carcinoma, Squamous Cell / Q000235:genetics; D003362:Cost-Benefit Analysis; D005188:False Negative Reactions; D005189:False Positive Reactions; D005260:Female; D015321:Gene Rearrangement; D006801:Humans; D007150:Immunohistochemistry / Q000191:economics; D017404:In Situ Hybridization, Fluorescence; D008175:Lung Neoplasms / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D020794:Receptor Protein-Tyrosine Kinases / Q000235:genetics* / Q000276:immunology*; D012680:Sensitivity and Specificity; D046888:Tissue Array Analysis
chemical_list: D000906:Antibodies; C000626173:ALK protein, human; D000077548:Anaplastic Lymphoma Kinase; D020794:Receptor Protein-Tyrosine Kinases