In: Breast Cancer Research, 19 (2017), Nr. 55. pp. 1-13. ISSN 1465-542X

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PDF, English Download (1MB) | Lizenz: An international reproducibility study validating quantitative determination of ERBB2, ESR1, PGR, and MKI67 mRNA in breast cancer using MammaTyper® by Varga, Zsuzsanna ; Lebeau, Annette ; Bu, Hong ; Hartmann, Arndt ; Penault-Llorca, Frederique ; Guerini-Rocco, Elena ; Schraml, Peter ; Symmans, Fraser ; Stoehr, Robert ; Teng, Xiaodong ; Turzynski, Andreas ; von Wasielewski, Reinhard ; Gürtler, Claudia ; Laible, Mark ; Schlombs, Kornelia ; Joensuu, Heikki ; Keller, Thomas ; Sinn, Hans-Peter ; Sahin, Ugur ; Bartlett, John ; Viale, Giuseppe underlies the terms of Creative Commons Attribution 3.0 Germany

Abstract

Background: Accurate determination of the predictive markers human epidermal growth factor receptor 2 (HER2/ERBB2), estrogen receptor (ER/ESR1), progesterone receptor (PgR/PGR), and marker of proliferation Ki67 (MKI67) is indispensable for therapeutic decision making in early breast cancer. In this multicenter prospective study, we addressed the issue of inter- and intrasite reproducibility using the recently developed reverse transcription-quantitative real-time polymerase chain reaction-based MammaTyper® test. Methods: Ten international pathology institutions participated in this study and determined messenger RNA expression levels of ERBB2, ESR1, PGR, and MKI67 in both centrally and locally extracted RNA from formalin-fixed, paraffin-embedded breast cancer specimens with the MammaTyper® test. Samples were measured repeatedly on different days within the local laboratories, and reproducibility was assessed by means of variance component analysis, Fleiss’ kappa statistics, and interclass correlation coefficients (ICCs). Results: Total variations in measurements of centrally and locally prepared RNA extracts were comparable; therefore, statistical analyses were performed on the complete dataset. Intersite reproducibility showed total SDs between 0.21 and 0.44 for the quantitative single-marker assessments, resulting in ICC values of 0.980–0.998, demonstrating excellent agreement of quantitative measurements. Also, the reproducibility of binary single-marker results (positive/negative), as well as the molecular subtype agreement, was almost perfect with kappa values ranging from 0.90 to 1.00. Conclusions: On the basis of these data, the MammaTyper® has the potential to substantially improve the current standards of breast cancer diagnostics by providing a highly precise and reproducible quantitative assessment of the established breast cancer biomarkers and molecular subtypes in a decentralized workup.