Abstract B044: Evaluation of ancestry-associated HER2 and androgen receptor expression in prostate cancer patients using liquid biopsy
Abstract
This study aims to define the role of HER2 in prostate cancer (PC) by investigating its association with West African genetic ancestry (WAA) and evaluating its potential as a complementary liquid biopsy biomarker. Black men suffer nearly double the incidence and mortality rate of PC compared to white men. This disparity persists after controlling for socioeconomic factors, suggesting biological determinants may drive differing outcomes. Androgen receptor (AR) drives tumor progression and is associated with PC aggressiveness. HER2, a tyrosine kinase receptor with no known ligand, promotes PC metastasis and is associated with recurrence. While HER2's role in breast cancer is well established, its function in PC remains obscure. HER2 overexpression has been associated with poor prognosis, advanced disease, higher Gleason score, and increased cell proliferation in PC, but these indicators have not been sufficiently evaluated in men of WAA. We hypothesize that Black men are more prone to HER2-positive PC and that HER2 expression positively correlates with WAA. Liquid biopsy offers a personalized, minimally invasive complement to tissue biopsy for cancer screening, prognosis, and disease monitoring, supporting a precision medicine approach. IRB approvals from Morehouse School of Medicine (MSM), Grady Memorial Hospital, and the University of Alabama at Birmingham were obtained to collect sera and plasma from consented patients (n=100) in a genitourinary oncology multidisciplinary clinic to evaluate HER2 and AR by liquid biopsy. In a separate MSM IRB-approved Discovery of Us study, 257 participants provided sera and plasma for liquid biopsy analysis, including HER2 and AR. Additionally, 40 participants were recruited at City of Hope (COH) in Duarte, CA (2018–2020) through a community-based prostate cancer screening program. ELISA was used across all samples to quantify circulating HER2 and AR, and ancestry estimates were obtained via validated genotyping. Preliminary data from 40 COH samples (23 self-identified white, 17 self-identified Black) revealed associations between HER2, AR, and WAA. Circulating HER2 and AR showed moderate correlation by self-reported race in both groups. Comparing circulating HER2 to WAA, Black men showed a positive correlation (0.2974). We are evaluating these correlations in our expanded cohort, with statistically analyzed results to be reported at the AACR Conference on The Science of Health Disparities. Thorough evaluation of HER2 by liquid biopsy may enhance risk stratification, identify patients who may benefit from HER2-targeted therapies, and complement established biomarkers such as PSA to improve diagnostic and prognostic accuracy. These findings support continued investigation of HER2-based liquid biopsy to advance precision medicine and individualized clinical management for prostate cancer. Diana T. LeVasseur, Jordan A. Ciuro, Shahid S. Ahmed, Sri L. Kollepara, Peter Kuhn, Jabril R. Johnson, Abdulrahman M. Dwead, Kevin S. Kimbro, Pam Cooper, Eddie Stanley, Kenisha L. Webb, Rick A. Kittles, Leanne Woods-Burnham. Evaluation of ancestry-associated HER2 and androgen receptor expression in prostate cancer patients using liquid biopsy [abstract]. In: Proceedings of the 19th AACR Conference on the Science of Cancer Health Disparities; 2026 Oct 18-21; Atlanta, GA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2026;35(10 Suppl):Abstract nr B044.