[Interlaboratory trial 2000 " Immunohistochemistry" of the German Society for Pathology and the Professional Association of German Pathologists]

Pathologists' Guideline Recommendations for Immunohistochemical Testing of Estrogen and Progesterone Receptors in Breast Cancer

Expression of the hormone receptors (estrogen receptor (ER) and progesterone receptor (PR)) as well as overexpression / amplification of the human epi-dermal growth factor receptor-2 (HER2) have not only been identified as important prognostic factors among patients with breast cancer. They have also been characterized as essential predictive factors for benefit derivable from endocrine treatment or immunologic therapies directed against HER2, respectively. Hence, reliable determination of hormone receptor and HER2 status among patients with breast cancer has become of utmost importance. The need for developing and promoting standard methodologies for the assessment of the individual disease phenotype has previously been acknowledged by publication of novel guidelines for HER2 testing. For HER2 testing, these guidelines have been developed in 2007 by the American Society of Clinical Oncology (ASCO) in conjunction with the American College of Pathology (CAP). Recently, ASCO/CAP have acknowledged the need for standardized assessment of hormone receptor status.We asked two experts in the field of breast pathology whether the new guidelines on hormone receptor testing would change current practice of hormone receptor status measurement in Germany and how they should be viewed in face of novel developments regarding gene expression based multigene predictive factors.Cornelia Liedtke, Münster and Oleg Gluz, Wuppertal.

Implementation of External Quality Assurance Trials for Immunohistochemically Determined Breast Cancer Biomarkers in Germany

Besides typing and grading of breast cancer, Pathologists are involved in the determination of biomarkers, such as steroid hormone receptors and HER2, which are of utmost importance in adjuvant therapy. There have been concerns with regard to security and reproducibility of the biomarker assays done on tissue sections applying either immunohistochemistry or in-situ hybridisation. In order to assure the quality of these biomarker assays, a number of measures are required, among them external proficiency testing. Therefore, external quality assurance trials have been implemented in Germany. In the period of 2002-2007, 5 consecutive trials were conducted with up to 180 participating laboratories. Tissue microarrays with 20-24 different breast cancer samples including cell lines enabled that a huge number of pathologists were challenged with identical samples which provides the prerequisite for comparability. Because there is no legal duress to undergo external proficiency testing in histopathology, all laboratories that took part volunteered to do so. These innovative quality assurance trials (Qualitätsinitiative Pathologie, QuIP) will be continued in the future on an annual or bi-annual basis. Participation is recommended for pathology departments involved in the service for breast units. The organisational frame work of the trials is described here.

Beyond typing and grading: target analysis in individualized therapy as a new challenge for tumour pathology

In order to bring about its beneficial effects in oncology, targeted therapy depends on accurate target analysis. Whether cells of a tumour will be sensitive to a specific treatment is predicted by the detection of appropriate targets in cancer tissue by immunohistochemistry or molecular methods. In most instances this is performed by histopathologists. Reliability and reproducibility of tissue-based target analysis in histopathology require novel measures of quality assurance by internal and external controls. As a model for external quality assurance in targeted therapy an annual inter-laboratory trial has been set up in Germany applying tissue arrays with up to 60 mammary cancer samples which are tested by participants for expression of HER2/neu and steroid hormone receptors.