193P - External quality assessment for ALK immunohistochemistry testing in lung adenocarcinoma within the European Thoracic Oncology Platform Lungscape Pro...

Date 30 September 2012
Event ESMO Congress 2012
Session Poster presentation II
Topics Biomarkers
Non-Small-Cell Lung Cancer, Metastatic
Presenter Erik Thunnissen
Authors E. Thunnissen1, K. Kerr2, L. Bubendorf3, D. Nonaka4, F.H. Blackhall5, R. Kammler6, E.J. Speel7, J. De Jong8, M. Martorell9, R.A. Stahel10
  • 1Pathology, Vrije Universiteit Medical Center, 1081 HV - Amsterdam/NL
  • 2Pathology, Aberdeen Royal Infirmary, AB25 2Z - Aberdeen/UK
  • 3Pathology, Universitätsspital Basel, 4031 - Basel/CH
  • 4Pathology, The Christie NHS Foundation Trust, M20 4BX - Manchester/UK
  • 5Medical Oncology, The Christie NHS Foundation Trust, M20 4BX - Manchester/UK
  • 6Translational Research Coordination, ETOP Coordinating Office, 3008 - Bern/CH
  • 7Pathology, Maastricht University Medical Centre, 6229 HX - Maastricht/NL
  • 8Pathology, The Netherlands Cancer Institute, 1066 CX - Amsterdam/NL
  • 9Pathology, Hosp. General Universitario de Valencia, 46014 - Valencia/ES
  • 10Clinic Of Oncology, Universitätsspital Zürich, 8091 - Zürich/CH

Abstract

Background

The External Quality Assessment (EQA) process in the scope of the Lungscape project of the European Thoracic Oncology Platform (ETOP) aims to detect the prevalence of ALK gene rearrangement in lung adenocarcinoma in Europe. To examine a large set of cases in a multi-institutional collaboration, standard protocols need to be established and tested. The aim of this EQA process was to examine the performance of ALK immunohistochemistry (IHC) in preparation for analysis of cases at each participating site.

Material and methods

For ALK immunohistochemistry the antibody clone 5A4 (Novocastra) was selected. Samples generated from cell lines and NSCLC resection specimens were used to construct a tissue microarray (TMA) for internal validation and a different TMA for external validation. Two protocols were established according to the resources available at participating laboratories: one for automated staining and one for a manual bench method. The protocols were validated using control samples by 2 laboratories each. Subsequently, the IHC protocols and TMA were provided to participating laboratories for internal validation. Subsequently external validation was performed using slides from another TMA, containing 5 positive cases and 5 controls. Participants were requested to use a modified (from Ruschoff) H-scoring system when reporting cases, to a maximum score of 200 (moderate/strong staining in 100% of cells).

Results

To date 14 labs have participated. 13 labs showed a performance in line with the expected result. The mean H-score out of a maximum of 200 for positive cases was 157 and for negative cases was 5. One of the positive cases was weakly to moderately positive in most labs (mean H-score 119). The remaining lab solved a staining issue and performed well on another TMA.

Conclusions

After guided internal validation, the external quality assessment showed excellent technical performance of ALK IHC in NSCLC. The process of EQA ensures uniformity and standardisation across participating laboratories, in preparation for analysis of archival samples for research.

Disclosure

All authors have declared no conflicts of interest.