Supplementary Material for: Androgen Receptor Gene Copy Number and Protein Expression in Treatment-Naïve Prostate Cancer

Objectives: To evaluate the androgen receptor (AR) gene
copy number in androgen deprivation therapy (ADT) treatment-naïve
prostate cancer (PCa) patients and to evaluate the corresponding AR
protein expression and assess the association between these features and
prognostic factors. Materials and Methods: Chromosome X
and AR gene copy number, using fluorescence-in-situ-hybridization, and
epithelial-stromal AR expression, using AR immunohistochemistry, were
analyzed in 62 ADT treatment-naïve PCa patients and 8
castration-refractory patients. Results: In ADT treatment-naïve PCa patients, the AR expression was higher in tumor epithelial cells versus surrounding stromal cells (p < 0.001) and versus normal epithelium in the same patient (p
= 0.043). The difference between tumoral AR expression and expression
in normal epithelium was higher in patients with ≥15% of tumor cells
with increased AR copy number (p = 0.019). Peritumoral stroma had
lower AR expression in patients with lymph-node or distant metastases
compared to those without metastases (p = 0.038). Conclusions:
This research evaluates the link between AR gene status, expression
profile, and possible prognostic factors. Furthermore, it highlights the
importance of the peritumoral environment in PCa. Additional research
is needed to further clarify the role of stromal AR in PCa dissemination
and identify possible therapeutic strategies to target this mechanism.