Abstract A061: The impact of race and obesity on the prostate tumor microenvironment
Authors: Galvan Gloria Cecilia , Mahov Simeon , You Sungyong , Knott Simon , Freeman Michael , Merchant Akil , Freedland Stephen J 
Published: September 2024

Black Americans have the highest prostate cancer incidence and are twice as likely to die from their disease compared to Non-Hispanic White men, making this one of the largest cancer disparities between these two racial groups in the United States. While access to health care is one of the strongest contributors to this disparity, studies suggest biological distinctions exist between tumors from Black and Non-Hispanic White men. Furthermore, obesity is associated with worse prostate cancer outcomes, and research showing a stronger association between obesity and prostate cancer risk among Black men compared to Non-Hispanic White men suggests obesity and Black race may work in combination to create aggressive disease. Hence, we sought to thoroughly and precisely characterize tumors from Black men, with and without obesity, to identify tumor behavior and potential therapeutic options for this population, which to date, has not been done mostly because of the lack of racially diverse cohorts of prostate cancer. Also, we sought to determine the impact of obesity on the composition of the prostate tumor microenvironment, which to date remains unknown. Given that in the US obesity rates are over 40% and the pressing need to better address high-risk populations, it is critical to better understand how obesity and race impact disease biology. We hypothesized obesity and Black race, individually and combined, increase tumor immune infiltration, creating a distinct tumor microenvironment. Specifically, we hypothesized this microenvironment will be characterized by higher overall inflammation, but also will enable us to identify therapeutic targets that in time can lead to the creation of personalized treatments for this population. To test this hypothesis, we used a large and racially diverse patient cohort from men who underwent radical prostatectomy at the Veterans Affairs Medical Center in Durham, North Carolina. To analyze the tumor microenvironment at the single cell level and define spatial organization, we used imaging mass cytometry in tissue microarrays of tumor and normal prostate samples from patients similar in tumor stage. We created a customized marker panel to determine cell phenotype and expression of immune checkpoints. We detected 25 cell phenotypes in the prostate microenvironment and determined differential phenotypic abundance and interactions by race and obesity. Next, we will expand our study to include a larger number of samples and associate tumor microenvironment characteristics with patient recurrence, metastasis, and survival. In this study, we generated new insights into disease drivers in an understudied and disproportionately affected population and lay important groundwork for future research identifying novel therapeutic targets for high-risk populations, such as men with African descent and obesity.

Citation Format: Gloria Cecilia Galvan, Simeon Mahov, Sungyong You, Simon Knott, Michael Freeman, Akil Merchant, Stephen J Freedland. The impact of race and obesity on the prostate tumor microenvironment [abstract]. In: Proceedings of the 17th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2024 Sep 21-24; Los Angeles, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2024;33(9 Suppl):Abstract nr A061.