Research article

Markers of subtypes in inflammatory breast cancer studied by immunohistochemistry: Prominent expression of P-cadherin

Azza Ben Hamida^1,3 , Intidhar S Labidi² , Karima Mrad⁴ , Emmanuelle Charafe-Jauffret^1,5,6 , Saïda Ben Arab³ , Benjamin Esterni⁷ , Luc Xerri⁵ , Patrice Viens^6,8 , François Bertucci^1,6,8 , Daniel Birnbaum¹ and Jocelyne Jacquemier^1,5

¹Centre de Recherche en Cancérologie de Marseille, Département d'Oncologie Moléculaire, UMR599 Inserm; Institut Paoli-Calmettes; IFR137, Marseille, France

²Département de Médecine, Institut Salah Azaiz, Tunis, Tunisie

³Unité d'Epidémiologie Génétique et Moléculaire, Faculté de Médecine, Tunis, Tunisie

⁴Département de Pathologie, Institut Salah Azaiz, Tunis, Tunisie

⁵Département de BioPathologie, Institut Paoli-Calmettes, Marseille, France

⁶UFR de Médecine, Université de la Méditerranée, Marseille, France

⁷Département de Biostatistiques, Institut Paoli-Calmettes, Marseille, France

⁸Département d'Oncologie Médicale, Institut Paoli-Calmettes, Marseille, France

author email corresponding author email

BMC Cancer 2008, 8:28doi:10.1186/1471-2407-8-28

Published:	29 January 2008

Abstract

Background

Inflammatory breast cancer (IBC) is a distinct and aggressive form of locally-advanced breast cancer with high metastatic potential. In Tunisia, IBC is associated with a high death rate. Among the major molecular subtypes, basal breast carcinomas are poorly differentiated, have metastatic potential and poor prognosis, but respond relatively well to chemotherapy. The aim of this study was to determine the distribution of molecular subtypes in IBC and identify factors that may explain the poor prognosis of IBC.

Methods

To determine breast cancer subtypes we studied by immunohistochemistry the expression of 12 proteins in a series of 91 Tunisian IBC and 541 non-IBC deposited in tissue microarrays.

Results

We considered infiltrating ductal cases only. We found 33.8% of basal cases in IBC vs 15.9% in non-IBC (p < 0.001), 33.3% of ERBB2-overexpressing cases in IBC vs 14.5% in non-IBC (p < 0.001), and 29.3% of luminal cases in IBC vs 59.9% in non-IBC (p < 0.001). The most differentially-expressed protein between IBCs and non-IBCs was P-cadherin. P-cadherin expression was found in 75.9% of all IBC vs 48.2% of all non-IBC (p < 0.001), 95% of IBC vs 69% of non-IBC (p = 0.02) in basal cases, and 82% of IBC vs 43% of non-IBC (p < 0.001) in luminal cases. Logistic regression determined that the most discriminating markers between IBCs and non-IBCs were P-cadherin (OR = 4.9, p = 0.0019) MIB1 (OR = 3.6, p = 0.001), CK14 (OR = 2.7, p = 0.02), and ERBB2 (OR = 2.3, p = 0.06).

Conclusion

Tunisian IBCs are characterized by frequent basal and ERBB2 phenotypes. Surprisingly, luminal IBC also express the basal marker P-cadherin. This profile suggests a specificity that needs further investigation.