Abstract PO5-03-08: Detection and quantification of triple-negative breast cancer (TNBC) across ethnicities through analysis of cell-free DNA (cfDNA) methylation

Abstract Introduction: Triple-negative breast cancer (TNBC) is an aggressive subtype contributing to race-related outcome disparities in breast cancer. These disparities are partly explained by the higher burden of TNBC in Black women, less access to new mammography technologies, and further compounded by limited efficacy of screening mammography in early detection of TNBC (Newman L 0.001) but no significant difference in mean TMeF between SRE groups (p = 0.09) with the distribution of TMeF (Table 2). The ANOVA additionally found a significant interaction between cancer stage and SRE (p 0.001) that could represent an impact of stage on TMeF that varied by SRE or differences in cancer stage distribution by SRE. Conclusions: In this pilot study, we observed that MCED testing was effective in detecting Stage II, III, and IV TNBC across SRE. These findings, in combination with the association of estimated ctDNA abundance with cancer stage but not patient SRE, provide hypothesis-generating evidence that analysis of methylation signals from across the genome can provide meaningful TNBC screening/detection information, independent of self-reported race/ethnicity. Table 1. MCED cancer detection rate by stage and SRE among TNBC patients. Table 2. Tumor methylated fraction (TMeF) by stage and SRE among TNBC patients. Citation Format: William Cance, Edison Liu, Margaret Antonio, Timothy Shaver, Stephannie Shih, Bong Chul Chu, Kathryn Kurtzman, Lisa Newman. Detection and quantification of triple-negative breast cancer (TNBC) across ethnicities through analysis of cell-free DNA (cfDNA) methylation abstract. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO5-03-08.