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Typical medullary breast carcinomas have a basal/myoepithelial phenotype

Authors

  • Jocelyne Jacquemier,

    Corresponding author
    1. Marseille Cancer Institute, Molecular Oncology Department, UMR599 INSERM and Paoli-Calmettes Institute, Marseille, France
    2. Biopathology Department, Paoli-Calmettes Institute, Marseille, France
    • Biopathology and Molecular Oncology Departments, Institut Paoli-Calmettes, 232 Bd. de Sainte Marguerite, 13009 Marseille, France.
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  • Laetitia Padovani,

    1. Biopathology Department, Paoli-Calmettes Institute, Marseille, France
    2. Genetic Oncology and Cancer Control Department, Paoli-Calmettes Institute, Marseille, France
    3. Oncology-Radiothérapy Départment, Centre Hospitalier Universitaire La Timone, Marseille, France
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  • Laetitia Rabayrol,

    1. Marseille Cancer Institute, Molecular Oncology Department, UMR599 INSERM and Paoli-Calmettes Institute, Marseille, France
    2. Genetic Oncology and Cancer Control Department, Paoli-Calmettes Institute, Marseille, France
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  • Sunil R Lakhani,

    1. The Breakthrough Tony Robins Breast Cancer Research Centre,' London, UK
    2. Molecular and Cellular Pathology, School of Medicine, University of Queensland, Brisbane, Australia
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  • Frédérique Penault-Llorca,

    1. Pathology Department, Jean Perrin Institute, Clermont-Ferrand, France
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  • Yves Denoux,

    1. Pathology Department, Centre François Baclesse, Caen, France
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  • Maryse Fiche,

    1. Pathology Department, Hôpital Laennec, St Herblain, France
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  • Paulo Figueiro,

    1. Pathology Department, Centre Régional d'Oncologie, Coimbra, Portugal
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  • Véronique Maisongrosse,

    1. Pathology Department, Claudius Regaud Institute, Toulouse, France
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  • Viviane Ledoussal,

    1. Pathology Department, Centre René Huguenin, St Cloud, France
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  • Jose Martinez Penuela,

    1. Pathology Department, Hôpital de Navarre, Pamplona, Spain
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  • Nora Udvarhely,

    1. Pathology Department, National Cancer Institute, Budapest, Hungary
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  • George El Makdissi,

    1. Biopathology Department, Paoli-Calmettes Institute, Marseille, France
    2. Genetic Oncology and Cancer Control Department, Paoli-Calmettes Institute, Marseille, France
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  • Christophe Ginestier,

    1. Marseille Cancer Institute, Molecular Oncology Department, UMR599 INSERM and Paoli-Calmettes Institute, Marseille, France
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  • Jeannine Geneix,

    1. Marseille Cancer Institute, Molecular Oncology Department, UMR599 INSERM and Paoli-Calmettes Institute, Marseille, France
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  • Emmanuelle Charafe-Jauffret,

    1. Marseille Cancer Institute, Molecular Oncology Department, UMR599 INSERM and Paoli-Calmettes Institute, Marseille, France
    2. Biopathology Department, Paoli-Calmettes Institute, Marseille, France
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  • Luc Xerri,

    1. Marseille Cancer Institute, Molecular Oncology Department, UMR599 INSERM and Paoli-Calmettes Institute, Marseille, France
    2. Biopathology Department, Paoli-Calmettes Institute, Marseille, France
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  • François Eisinger,

    1. Genetic Oncology and Cancer Control Department, Paoli-Calmettes Institute, Marseille, France
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  • Daniel Birnbaum,

    1. Marseille Cancer Institute, Molecular Oncology Department, UMR599 INSERM and Paoli-Calmettes Institute, Marseille, France
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  • Hagay Sobol

    1. Marseille Cancer Institute, Molecular Oncology Department, UMR599 INSERM and Paoli-Calmettes Institute, Marseille, France
    2. Genetic Oncology and Cancer Control Department, Paoli-Calmettes Institute, Marseille, France
    3. Medical School, Aix-Marseille II University, Marseille, France
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Abstract

Medullary breast cancer (MBC) is a rare, diagnostically difficult, pathological subtype. Despite being high grade, it has a good prognosis. MBC patients have an excess of BRCA1 germ-line mutation and reliable identification of MBC could help to identify patients at risk of carrying germline BRCA1 mutations or in whom chemotherapy could be avoided. The aim of this study was therefore to improve diagnosis by establishing an MBC protein expression profile using immunohistochemistry (IHC) on tissue-microarrays (TMA). Using a series of 779 breast carcinomas (‘EC’ set), diagnosed initially as MBC, a double-reading session was carried out by several pathologists on all of the histological material to establish the diagnosis as firmly as possible using a ‘medullary score’. Only MBCs with high scores, i.e. typical MBC (TMBC) (n = 44) and non-TMBC grade III with no or low scores (n = 160), were included in the IHC study. To validate the results obtained on this first set, a control series of TMBC (n = 17) and non-MBC grade III cases (n = 140) (‘IPC’ set) was studied. The expression of 18 proteins was studied in the 61 TMBCs and 300 grade III cases from the two sets. The global intra-observer concordance of the first reading for the diagnosis of TMBC was 94%, with almost perfect κ (kappa) of 0.815. TMBC was characterized by a high degree of basal/myoepithelial differentiation. In multivariate analysis with logistic regression, TMBC was defined by the association of P-cadherin (R = 2.29), MIB1 > 50 (R = 3.80), ERBB2 negativity (R = 2.24) and p53 positivity (RR = 1.45). Copyright © 2005 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

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