Abstract
The impact of G protein-coupled oestrogen receptor 1 on male breast cancer: a retrospective analysis
- Department of Pathology, Otto von Guericke University Magdeburg, Magdeburg, Germany
- Institute of Pathology, Neuropathology and Molecular Pathology, Medical University of Innsbruck, Innsbruck, Austria
- Department of Pathology, Dessau Medical Centre, Dessau, Germany
- Institute for Biometrics and Medical Informatics, Otto von Guericke University Magdeburg, Magdeburg, Germany
- Department of Biostatistics and Translational Medicine, Medical University of Lodz, Lodz, Poland
- Department of Radiation Oncology, Dana-Farber Cancer Institute, Boston, MA, USA
- Clinic for Internal Medicine I, Dessau Medical Centre, Dessau, Germany
- Diagnostic & Research Centre for Molecular Biomedicine, Institute of Pathology, Medical University of Graz, Graz, Austria
- Center for Biomarker Research in Medicine, Graz, Austria
- Department of Obstetrics and Gynaecology, Otto von Guericke University Magdeburg, Magdeburg, Germany
- Department of Obstetrics and Gynaecology, Hospital Magdeburg GmbH, Magdeburg, Germany
Introduction
The G protein-coupled oestrogen receptor 1 (GPER-1) is a potential prognostic marker in breast cancer. However, its role in male breast cancer (MBC) is still unknown. This study evaluates the expression of GPER-1 in MBC samples and correlates these data with clinical and pathological parameters including patients’ survival.
Material and methods
For this retrospective analysis of a prospectively maintained cohort of patients with MBC, we examined 161 specimens for GPER-1 expression using immunohistochemistry. An immunoreactive score (IRS) was calculated based on staining intensity and the percentage of positive tumour cells. Then, we correlated GPER-1 IRS with clinical and pathological parameters, and overall and relapse-free survival.
Results
About 40% of MBC samples were positive for GPER-1 expression (IRS ≥ 4). There was no significant correlation with clinicopathological parameters, such as hormone receptor status or grading. However, a statistical trend was observed for tumour size (≥ 2 cm, p = 0.093). Kaplan-Meier survival analysis revealed no significant correlation with relapse-free survival. However, there was a significant correlation with overall survival, but when we adjusted the log-rank p-value to compensate for the cut-off point optimization method, it rose above 0.1. Additionally, GPER-1-positive patients were older at diagnosis. When adjusted for age by multivariable Cox regression analysis, the significance of GPER-1 status for survival was further reduced.
Conclusions
We found no significant prognostic value of GPER-1 in this MBC cohort as anticipated from studies on female BC. Future studies with higher sample size are needed to further verify a potential sex-specific role of GPER-1.
Keywords
male breast cancer, MBC, survival analysis, GPER-1, GPR30, OS, RFS
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