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Glenn Francis

Immunohistochemistry Quality Assurance Program in Australasia: An Update

Handout (pdf 73p)

Handout (pdf 19p)

Abstract:

Immunohistochemistry (IHC) is essential for the diagnosis of tumours and there is an increasing role of IHC to provide prognostic and predictive information to determine treatment decisions for patients.  IHC is being integrated as a biomarker into the anatomical pathology report for multiple tumour types including breast carcinoma and non-small cell lung carcinoma together with in-situ hybridisation (ISH) and molecular biomarkers. In breast carcinoma the accurate assessment of oestrogen receptor (ER), Progesterone receptor (PR) and HER2 status is essential for appropriate patient care.

The immunohistochemistry (IHC) Quality Assurance Program (QAP) includes a number of modules: diagnostic, lymphoma markers, breast markers, bright-field HER2 ISH and technical. Other countries have similar quality assurance programs (1-4).

Methods

The IHC modules consist of a number of technical exercises per year with assessment of different biomarkers. The breast markers module evaluates oestrogen receptor, progesterone receptor and HER2 with a separate component for bright-field HER2 ISH testing. An audit of patient results is also performed for the breast biomarkers.  The diagnostic module comprises four cases per year and mimics the use of IHC in diagnostic practice. The IHC technical module assesses laboratory proficiency in performing specified IHC markers and the lymphoma module evaluates IHC markers used in the diagnosis of lymphoma.

Slides are sent to participants comprising either tissue microarray blocks or composite blocks from different tissues.

Homogeneity and stability testing are performed on the sections and every 20th section is stained to ensure representative tissue. Antigenic site stability is also evaluated.

Slides are stained by the participating laboratory and returned for evaluation by a committee of scientists and pathologists. Each slide is evaluated independently and an average score is returned.  Each slide is scored from 0 to 5. The assessment criteria used are:

  • Intensity of true positivity is of reasonable strength
  • Absence of background staining (good signal to noise ratio)
  • Sensitivity – all target tissues labelled
  • Localisation – only target antigenic sites labelled
  • Chromogen character – crisp and distinct
  • Counterstain quality – complementary not obscuring
  • Absence of artifacts
  • Adequacy of controls – sufficiently sensitive.

A score <2.5 is considered unsatisfactory, 2.5-3.0, borderline and a score ≥3.0 is satisfactory.

Control slides are not assessed.

Results

Participants’ results vary depending on the module being assessed and there has generally been an improvement of results over time, however deficiencies are still noticed for some biomarkers. Results of the various modules will be presented. Click to see the graphs.

Discussion

Immunohistochemistry and ISH are used as an aid in the diagnosis of patients’ tumours and to determine patient treatment. Poor quality IHC and ISH will have a significant impact on patient outcome. It is therefore essential that the results generated by the laboratory are accurate. External QAP forms an essential part of laboratory assessment.

During the discussion of results, participants frequently raise the concern that the supplied material from the QAP is different to their in-house samples and that the supplied material does not accurately reflect the laboratory’s results. This statement does not recognize the difference between Quality Control and Quality Assurance. The in-house controls, even if placed on the same slide, are Quality Controls and indicate that the antibody and the detection system are working. They do not indicate whether the result obtained is in fact correct and accurate. This is well recognized in clinical pathology where a method is validated against a reference method to determine accuracy and then QC is run internally to ensure that the reagents and instruments are working. In many cases for IHC and ISH the controls selected are inappropriate, excessively large, show fixation variation or only reflect one level of staining.

Conclusion

High quality IHC and ISH results are essential to enable treating clinicians to optimise therapy for patients. The introduction and expansion of a specific quality assurance module for IHC and ISH has enabled an ongoing assessment of the performance of biomarkers in Australia, New Zealand and South-East Asia. Despite the extraction of large amounts of information in regards to the methodology used for staining, it is usually not possible to identify one specific method that results in optimal staining although sample methods with high marks are reported.

Optimisation of retrieval for a wide range of sensitivities is considered to be the important factor in achieving satisfactory results. The development of the program has resulted in an improvement in the staining quality for a number of biomarkers.

References  

1. Regitnig P, Reiner A, Dinges HP, Hofler G, Muller-Holzner E, Lax SF, et al. Quality assurance for detection of estrogen and progesterone receptors by immunohistochemistry in Austrian pathology laboratories. Virchows Arch. 2002;441(4):328-34.
2. Yaziji H, editor Discrepancies between immunohistochemistry and fluorescence in -situ hybridization for HER-2 testing in breast cancer: The role of a quality assurance program on a cohort of 3564 patients. ASCO; 2004.
3. Chen ZW, Neufeld H, Copete MA, Garratt J, Gilks CB, Torlakovic EE. Academic and Nonacademic Laboratories Perform Equally on CIQC Immunohistochemistry Proficiency Testing. American Journal of Clinical Pathology. 2013;140(1):55-60.
4. Torlakovic EE, Francis G, Garratt J, Gilks B, Hyjek E, Ibrahim M, et al. Standardization of negative controls in diagnostic immunohistochemistry: recommendations from the international ad hoc expert panel. Applied immunohistochemistry & molecular morphology : AIMM / official publication of the Society for Applied Immunohistochemistry. 2014;22(4):241-52.

Immunohistochemistry Advisory Committee:

Beena Kumar
A/Prof Glenn Francis
Xiao Juan Wu
Alex Laslowski
Michael Platten
David Gan
Ruth Davis
Sharita Meharry

Comments in this report were prepared for and on behalf of the RCPA Quality Assurance Programs Pty Limited by Dr Glenn Francis.
© This material is copyright and may not be used in any form for advertising, sales promotion or publicity. The material may not be reproduced in whole or in part for any purpose whatsoever (including presentations at meetings and conferences), without the prior written permission of the RCPA Quality Assurance Programs Pty Limited. Permission must be sought in writing from the Program but will not be unreasonably refused.
RCPA Quality Assurance Programs keeps all participant details confidential. Such details will not be disclosed to a third party, unless required by legislation, without the prior written consent of the participant.

CV

Dr Glenn Francis MBBS FRCPA MBA FFSc (RCPA)

Dr Glenn Francis graduated from the University of Queensland in 1984 (MBBS Hons) and subsequently trained in general pathology. Following completion of his training in 1991, he began work in a private pathology laboratory based in Redcliffe. He established a new private laboratory in Rockhampton Central Queensland in 1994 with additional laboratories in Emerald and Townsville. Dr Francis developed an interest in breast and molecular pathology and became Convener of the RCPA Immunohistochemistry Quality Assurance Program (RCPA QAP Pty Ltd) in 2001. In 2002, he relocated to the Gold Coast and was appointed Pathologist in charge of the Gold Coast and Northern Rivers region in a private pathology laboratory. In 2005 he was appointed Director of Pathology Princess Alexandra Hospital Brisbane and established the Molecular and Clinical Pathology Research Laboratory in 2008. In 2011 he was appointed as Medical Director Pathology Queensland Central Laboratory (Royal Brisbane, Women's and Children's Hospitals) and initiated the molecular testing program for the RCPA QAP for mutations in EGFR, BRAF and KRAS. In late 2013 he returned to private pathology practice and established a private molecular diagnostic pathology laboratory, Genomics For Life.

Dr Francis has a special interest in molecular pathology and personalised medicine. His current appointments include Adjunct Associate Professor Griffith University, Adjunct Associate Professor Australian Institute for Bioengineering and Nanotechnology University of Queensland, President Australasian Immunohistochemistry Society, Molecular Pathology Advisory Board, EGFR IHC Expert Panel, RCPA Tissue Banking Working Party, Assessor for the National Association of Testing Authorities, RCPA General Pathology Advisory Committee, RCPA Genetic Pathology Advisory Committee, RCPA Cancer Services Advisory Committee and MSAC Expert Standing Panel.

His current research activities include prognostic biomarkers in breast cancer, molecular biology, diagnostic oncology, next generation sequencing, neural network applications in pathology, immunohistochemistry and in-situ hybridization. Collaborative research is being performed in conjunction with the Queensland Institute of Medical Research, University of Queensland, Queensland University of Technology, The Garvan Institute and the Peter MacCallum Cancer Institute.

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KONXION A/S