Molecular apocrine breast cancers are aggressive estrogen receptor negative tumors overexpressing either HER2 or GCDFP15
- Equal contributors
1 AP-HP, Hosp Saint-Louis, Laboratory of Biochemistry, 1 av C. Vellefaux, Paris, 75010, France
2 CNRS UMR7212/INSERMU944, IUH, 1 av C. Vellefaux, Paris, 75010, France
3 University Paris Diderot, Sorbonne Paris Cité, Paris, 75010, France
4 AP-HP, Hosp Saint-Louis, Breast Diseases Center, 1 av C. Vellefaux, Paris, 75010, France
5 AP-HP, Hosp Saint-Louis, Biostatistic Department, 1 av C. Vellefaux, Paris 75010, France
6 AP-HP, Hosp Saint-Louis, Laboratory of Pathology, 1 av C. Vellefaux, Paris, 75010, France
7 INSERM UMR_S728, 1 av C. Vellefaux, Paris, 75010, France
8 AP-HP, Hosp Saint-Louis, Department of Surgery, 1 av C. Vellefaux, Paris, 75010, France
9 AP-HP, Hosp Saint-Louis, Department of Radiology, 1 av C. Vellefaux, Paris, 75010, France
Breast Cancer Research 2013, 15:R37 doi:10.1186/bcr3421Published: 11 May 2013
Molecular apocrine (MA) tumors are estrogen receptor (ER) negative breast cancers characterized by androgen receptor (AR) expression. We analyzed a group of 58 transcriptionally defined MA tumors and proposed a new tool to identify these tumors.
We performed quantitative reverse transcription PCR (qRT-PCR) for ESR1, AR, FOXA1 and AR-related genes, and immunohistochemistry (IHC) for ER, PR, Human Epidermal Growth Factor Receptor 2 (HER2), CK5/6, CK17, EGFR, Ki67, AR, FOXA1 and GCDFP15 and we analyzed clinical features.
MA tumors were all characterized by ESR1(-) AR(+) FOXA1(+) and AR-related genes positive mRNA profile. IHC staining on these tumors showed 93% ER(-), only 58% AR(+) and 90% FOXA1(+). 67% and 57% MA tumors were HER2(3+) and GCDFP15(+), respectively. Almost all MA tumors (94%) had the IHC signature HER2(3+) or GCDFP15(+) but none of the 13 control basal-like (BL) tumors did. Clinically, MA tumors were rather aggressive, with poor prognostic factors.
MA tumors could be better defined by their qRT-PCR-AR profile than by AR IHC. In addition, we found that HER2 or GCDFP15 protein overexpression is a sensitive and specific tool to differentiate MA from BL in the context of ER negative tumors. A composite molecular and IHC signature could, therefore, help to identify MA tumors in daily practice.