Correlation of IHC and FISH for ALK gene rearrangement in non-small cell lung carcinoma: IHC score algorithm for FISH

J Thorac Oncol. 2011 Mar;6(3):459-65. doi: 10.1097/JTO.0b013e318209edb9.


Introduction: Accurate, cost-effective methods for testing anaplastic lymphoma kinase gene rearrangement (ALK+) are needed to select patients with non-small cell lung carcinoma for ALK-inhibitor therapy. Fluorescent in situ hybridization (FISH) is used to detect ALK+, but it is expensive and not routinely available. We explored the potential of an immunohistochemistry (IHC) scoring system as an affordable, accessible approach.

Methods: One hundred one samples were obtained from an enriched cohort of never-smokers with adenocarcinoma from the Mayo Clinic Lung Cancer Cohort. IHC was performed using the ALK1 monoclonal antibody with ADVANCE detection system (Dako) and FISH with dual-color, break-apart probe (Abbott Molecular) on formalin-fixed, paraffin-embedded tissue.

Results: Cases were assessed as IHC score 0 (no staining; n = 69), 1+ (faint cytoplasmic staining, n = 21), 2+ (moderate, smooth cytoplasmic staining; n = 3), or 3+ (intense, granular cytoplasmic staining in ≥10% of tumor cells; n = 8). All IHC 3+ cases were FISH+, whereas 1 of 3 IHC 2+ and 1 of 21 IHC 1+ cases were FISH+. All 69 IHC 0 cases were FISH-. Considering FISH a gold-standard reference in this study, sensitivity and specificity of IHC were 90 and 97.8%, respectively, when 2+ and 3+ were regarded as IHC positive and 0 and 1+ as IHC negative.

Conclusions: IHC scoring correlates with FISH and may be a useful algorithm in testing ALK+ by FISH in non-small cell lung carcinoma, similar to human epidermal growth factor-2 testing in breast cancer. Further study is needed to validate this approach.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenocarcinoma / diagnosis*
  • Adenocarcinoma / genetics
  • Adenocarcinoma / metabolism
  • Adult
  • Aged
  • Algorithms
  • Anaplastic Lymphoma Kinase
  • Carcinoma, Non-Small-Cell Lung / diagnosis*
  • Carcinoma, Non-Small-Cell Lung / genetics
  • Carcinoma, Non-Small-Cell Lung / metabolism
  • Cohort Studies
  • Female
  • Follow-Up Studies
  • Gene Rearrangement*
  • Humans
  • Immunoenzyme Techniques
  • In Situ Hybridization, Fluorescence*
  • Lung Neoplasms / diagnosis*
  • Lung Neoplasms / genetics
  • Lung Neoplasms / metabolism
  • Male
  • Middle Aged
  • Neoplasm Staging
  • Prognosis
  • Receptor Protein-Tyrosine Kinases / genetics*
  • Receptor Protein-Tyrosine Kinases / metabolism*
  • Sensitivity and Specificity


  • ALK protein, human
  • Anaplastic Lymphoma Kinase
  • Receptor Protein-Tyrosine Kinases