Abstract A050: The impact of air pollution on aggressive breast cancer prognoses in women of African descent

Abstract Significance. Breast cancer (BC) is the most diagnosed cancer among women in the US. Though highly heterogeneous, different subtypes can be characterized by the expression of membrane receptors on the cell surface: ER+, HER2+, PR+, or basal-like which does not express any of the three receptors. Basal-like triple-negative breast cancer (TNBC) is a highly aggressive subtype of BC that represents about 15% of overall BC cases. Black women disproportionately experience higher rates of early-onset TNBC phenotypes and worse prognoses when compared to White women. Though genetics is a key factor in oncogenesis and cancer progression, it is now widely recognized that differences in cancer outcomes are influenced, also, by various environmental, social, and lifestyle factors known collectively as the social determinants of health (SDOH). For example, air pollution has consistently been shown to be associated with an increased risk of breast cancer, however, little is known about how air pollution alters biological and molecular mechanisms impacting breast cancer progression. Elucidating these influential factors is critical to understanding and addressing disparate outcomes. We are interested in understanding how air pollution impacts immune-oncology related proteins in breast cancer, specifically for Black and White women living in Baltimore City, Maryland. Methods. In a cohort of 217 women (142 Black, 75 White), we performed statistical analyses to determine the correlation between particulate matter 2.5 (PM2.5) with breast cancer subtype and oncogenic molecular drivers within the tumor and its microenvironment. PM2.5 concentration for Census year 2000 was measured using the EPA Downscale Model. Concentrations at the census-tract level were then linked to each participant's geocoded residential address at study baseline. Results. [BJ1] Our data reveal that a higher exposure to PM2.5 is correlated with breast cancer subtypes incidences[BJ2] (p- value[BJ3] =0.051), specifically for hormone receptor positive (ER+ and/or PR+) and TNBC subtypes (p-value=0.035). Elevated air pollution is also associated with estrogen-receptor status overall (p-value=0.002) and in Black (p-value=0.043) and White (p-value=0.008) women in the stratified analysis. Serum protein measurements in this cohort also revealed significant relationships between elevated air pollution and immune-oncology related proteins, including PD-L1, CAIX, CXCL9, and MCP-2.Discussion. Our preliminary evidence reveals an association between air pollution, breast cancer subtypes, and immune-oncology related proteins, with some of these relationships affecting Black and White populations differently. We will continue to interrogate these differences and begin to reveal the underlying mechanisms exacerbating breast cancer disparities. Citation Format: Kayla S. Ingram, Brittany Jenkins-Lord. The impact of air pollution on aggressive breast cancer prognoses in women of African descent [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 A050.