Abstract 686: Retrospective analysis of estrogen receptor expression in prostatic neoplasms: Implications across age and racial groups

Abstract Background: Prostate cancer (PCa) is the most common cancer in men in the United States, aside from non-melanoma skin cancer. The roles of estrogen receptor α (ERα) and estrogen Receptor β (ERβ) in PCa have not been fully elucidated yet. This study aims to evaluate the expression levels and localizations of ERα and ERβ in benign prostatic tissue (BPT) and PCa across different racial and age groups. Methods: Immunohistochemistry (IHC) for ERα and ERβ was performed on tissue microarrays (TMA) containing 240 samples of BPT and PCa from Black and White individuals and age groups ≤60 and >60 years. The localization of the IHC signal for ERα and ERβ was determined in glandular and stromal regions. Expression levels of ERα and ERβ were quantified using an IHC score, calculated by multiplying the area score (percentage of stained cells: 0 for no staining, 1 for <10% staining, 2 for 10-50% staining, and 3 for >50% staining) by the intensity score (0 for no signal, 1 for weak, 2 for moderate, and 3 for strong staining). Statistical analysis was performed using Student's t-test; a p-value ≤0.05 was considered significant. Results: In the entire population, the IHC scores for glandular ERα, stromal ERα, and glandular ERβ were lower in all PCa cases than in BPT, but a significant difference was only seen in glandular ERβ between PCa and BPT (3.43±2.3 vs. 4.86±2.8; p=0.0021). Interestingly, the IHC scores for all glandular ERα, stromal ERα, and glandular ERβ were significantly lower in metastatic PCa than in BPT (p=0.014, p=0.0001, and p=0.0035, respectively). While the entire population was stratified by race, there was no significant difference in IHC score for glandular ERα, stromal ERα, or glandular ERβ in both BPT and PCa between Black and white populations. While entire population was stratified by age, individuals with age >60 years had significantly lower IHC scores for glandular ERα (p=0.0023) and stromal ERα (p=0.03), but not for and glandular ERβ (p=0.1) in BPT; and significantly lower IHC score for stromal ERα (p=0.0036). Conclusions: These findings suggest that ERα and ERβ could be potentially diagnostic and prognostic biomarkers for PCa. Declined expression levels of glandular ERα, stromal ERα, and glandular ERβ may correlate to the oncogenesis, progression and disparities in race and age PCa. Citation Format: Laura B. Pagan, Tingting Yang, Jinghe Mao, Xinchun Zhou. Retrospective analysis of estrogen receptor expression in prostatic neoplasms: Implications across age and racial groups [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 686.