Abstract C142: Differential single-cell spatial immune cell profiles and immune cell interactions identified within lymph nodes metastases of black and white women diagnosed with triple negative breast cancers

Abstract Ethnic disparities in breast cancer (BC) outcomes have been reported, with lower survival rates among black women compared to white. Additionally, the unfavorable triple negative (TNBC) sub-type is more prevalent in black women and within this population, risk of mortality is again higher compared to white women. Biological contributors to this disparity are less clearly understood than socio-economic factors. Recent studies recognize different breast tumour immune microenvironments between black and white BC patients, necessitating further research into ethnicity-related differences in anti-tumor immune responses. Such responses begin in regional lymph nodes (LNs) with tumor neoantigen presentation. Here, we generate single-cell spatial maps of involved TNBC LN cores in treatment naïve black and white women. To guide design of a phenotyping panel for LNs, we profiled blood samples (n=95) using high-dimensional flow cytometry from newly diagnosed black and white BC patients. We found differential skewing of NK cell subsets, lower memory B cell (identified as IgM+CD27+IgD- 2024 Sep 21-24; Los Angeles, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2024;33(9 Suppl):Abstract nr C142.