37P - Androgen Receptor expression in a population-based prospective breast cancer cohort
|Date||08 May 2014|
|Session||Welcome reception and Poster Walk|
|Topics|| Breast Cancer
|Citation||Annals of Oncology (2014) 25 (suppl_1): i8-i16. 10.1093/annonc/mdu066|
K. Elebro1, S. Borgquist1, M. Simonsson1, A. Markkula1, C. Rose2, C. Ingvar3, H. Jernström1
The importance of the androgen receptor (AR) as a prognostic and treatment predictive factor in breast cancer is currently debated. In previous studies, we have demonstrated a treatment predictive value of AR genotyping as for adjuvant tamoxifen, but not for aromatase inhibitors. The aim of this study was to evaluate AR expression in relation to tumor and patient characteristics in the same cohort; the BC Blood study.
Materials and methods:
This prospective cohort of 1026 patients diagnosed with primary invasive breast cancer at Skane University Hospital, Lund, Sweden, between Oct 2002 and Jun 2012 was followed until Dec 2012. At baseline, preoperative questionnaires assessed lifestyle and reproductive history and body measurements were taken. Clinical data were collected from patient charts and pathology reports. Tissue microarrays were constructed for immunohistochemical assessment of AR expression (AR441, Thermo Scientific, classified as positive if >10% stained nuclei). Statistical analyses on AR status (positive/negative) in relation to tumor- and patient characteristics were performed by Chi Square test and Odds Ratio (OR).
Among the 1026 patients AR expression was assessable in 913 tumors. A total of 776 (85%) were classified as AR positive and 137 (15%) were AR negative. AR was co-expressed with the estrogen receptor (ER) and the progesterone receptor (PR) (ORER12.53 (95%CI 8.05–19.50), ORPR4.81 (3.29–7.03)). AR positivity correlated to smaller invasive tumor size ≤20 mm (OR<20 mm1.43 (0.98–2.11) and lower histological grade (ORI−IIvsIII5.17 (3.53–7.57)), but not axillary nodal involvement. AR expression was associated with higher age (OR50+yrs1.66 (1.08–2.54). Body Mass Index (BMI) and waist-hip-ratio (WHR) were not associated with AR expression.
The AR findings in this study were partly new. The distribution of tumor characteristics in relation to AR status confirmed results in previous similar studies. AR expression was significantly associated with age, but not with BMI and WHR. Further studies on AR are of interest since AR might be an important target for therapy and a supplement to standard hormonal factors such as ER and PR to predict response to treatment.
All authors have declared no conflicts of interest.