title: Combination of conventional immunohistochemistry and qRT-PCR to detect ALK rearrangement.
abstract: BACKGROUND
  Compared with FISH and qRT-PCR analyses, immunohistochemistry (IHC) is the preferred screening test in most pathology practices for ALK-rearrangement detection. With 100% sensitivity and 98% specificity, the VENTANA ALK (D5F3) IHC assay has been approved in the EU and some Asian countries for ALK-rearrangement detection. However, an automated Ventana IHC platform is not available in most pathology labs. In this study, we evaluated the applicability of conventional IHC with D5F3 antibody in routine pathological practice and proposed detection methods and procedures that ensure that patients with ALK+ are not missed.
  
  
  METHODS
  FISH and IHC analyses were performed on 297 lung adenocarcinoma cases. VENTANA IHC and qRT-PCR assay were applied to evaluate ALK-fusion status in the discordant cases of FISH and IHC. The association of ALK+ with clinicopathological characteristics was statistically analyzed.
  
  
  RESULTS
  IHC had 100% sensitivity and 81.8% specificity for detecting ALK+. Eight ALK-expressed cases were ALK-, five of which had ALK fusion detected by qRT-PCR analysis. Three of these five cases showed ALK expression using VENTANA IHC assay. ALK+ was associated with younger age and lymph node metastasis in this Chinese lung adenocarcinoma patient cohort.
  
  
  CONCLUSIONS
  The advantages of low cost and 100% sensitivity allow conventional IHC to serve as a robust diagnostic tool for screening patients with ALK+, especially in pathology labs without a VENTANA IHC platform. For cases in which ALK is weakly expressed, qRT-PCR is necessary as a diagnostic test for ALK-fusion detection.
  The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/2269448351088278.
authors.forename: Ling
authors.initials: L
authors.lastname: Shan
authors.forename: Fang
authors.initials: F
authors.lastname: Lian
authors.forename: Lei
authors.initials: L
authors.lastname: Guo
authors.forename: Xin
authors.initials: X
authors.lastname: Yang
authors.forename: Jianming
authors.initials: J
authors.lastname: Ying
authors.affiliation: Department of Pathology, Cancer Institute & Hospital, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing, 100021, China. lindm3@163.com.
authors.forename: Dongmei
authors.initials: D
authors.lastname: Lin
mesh_terms: D000230:Adenocarcinoma / Q000235:genetics*; D000077192:Adenocarcinoma of Lung; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000077548:Anaplastic Lymphoma Kinase; D005260:Female; D015321:Gene Rearrangement; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods*; D017404:In Situ Hybridization, Fluorescence; D008175:Lung Neoplasms / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D060888:Real-Time Polymerase Chain Reaction / Q000379:methods*; D020794:Receptor Protein-Tyrosine Kinases / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods*; D046888:Tissue Array Analysis; D055815:Young Adult
chemical_list: C000626173:ALK protein, human; D000077548:Anaplastic Lymphoma Kinase; D020794:Receptor Protein-Tyrosine Kinases