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Typical medullary breast carcinomas have a basal/myoepithelial phenotype
Author(s) -
Jacquemier Jocelyne,
Padovani Laetitia,
Rabayrol Laetitia,
Lakhani Sunil R,
PenaultLlorca Frédérique,
Denoux Yves,
Fiche Maryse,
Figueiro Paulo,
Maisongrosse Véronique,
Ledoussal Viviane,
Martinez Penuela Jose,
Udvarhely Nora,
El Makdissi George,
Ginestier Christophe,
Geneix Jeannine,
CharafeJauffret Emmanuelle,
Xerri Luc,
Eisinger François,
Birnbaum Daniel,
Sobol Hagay
Publication year - 2005
Publication title -
the journal of pathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.964
H-Index - 184
eISSN - 1096-9896
pISSN - 0022-3417
DOI - 10.1002/path.1845
Subject(s) - myoepithelial cell , immunohistochemistry , breast cancer , medicine , tissue microarray , concordance , pathology , medullary cavity , kappa , oncology , cancer , linguistics , philosophy
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.