Canadian anaplastic lymphoma kinase study: a model for multicenter standardization and optimization of ALK testing in lung cancer.

Abstract

INTRODUCTION:

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: Jean-Claude Cutz, Kenneth J Craddock, Emina Torlakovic, Guilherme Brandao, Ronald F Carter, Gilbert Bigras, Jean Deschenes, Iyare Izevbaye, Zhaolin Xu, Wenda Greer, Yasushi Yatabe, Diana Ionescu, Aly Karsan, Sungmi Jung, Richard S Fraser, Miriam Blumenkrantz, Josee Lavoie, Flechere Fortin, Anna Bojarski, Gilbert B Côté, Janette A van den Berghe, Fariborz Rashid-Kolvear, Martin Trotter, Harmanjatinder S Sekhon, Roula Albadine, Danh Tran-Thanh, Isabelle Gorska, Joan H M Knoll, Jie Xu, Ben Blencowe, A John Iafrate, David M Hwang, Melania Pintilie, Rania Gaspo, Christian Couture, Ming-Sound Tsao
• Journal: Journal of thoracic oncology : official publication of the International Association for the Study of Lung Cancer (J Thorac Oncol) Vol. 9 Issue 9 Pg. 1255-63 (Sep 2014) ISSN: 1556-1380 [Electronic] United States
• PMID: 25122422 (Publication Type: Journal Article, Multicenter Study, Randomized Controlled Trial, Research Support, Non-U.S. Gov't)

Chemical References

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

Topics

• Adenocarcinoma (diagnosis, enzymology, genetics)
• Adenocarcinoma of Lung
• Anaplastic Lymphoma Kinase
• Canada
• DNA, Neoplasm (genetics)
• Female
• Follow-Up Studies
• Humans
• Immunohistochemistry
• In Situ Hybridization, Fluorescence (methods)
• Lung Neoplasms (diagnosis, enzymology, genetics)
• Male
• Middle Aged
• Prospective Studies
• Receptor Protein-Tyrosine Kinases (genetics, metabolism)
• Reproducibility of Results
• Reverse Transcriptase Polymerase Chain Reaction