Abstract P1-03-05: RNA-sequencing data in diverse women diagnosed with ductal carcinoma in situ

Abstract Black women have a higher risk of subsequent breast cancer events (SBEs) but are underrepresented in ductal in situ carcinoma (DCIS) biomarker research compared to Non-Hispanic White women. We performed RNA sequencing using the Illumina NovaSeq 6000 technology on formalin-fixed paraffin embedded (FFPE) DCIS specimens. We integrated transcript data with clinical and social factors that drive SBEs in the Resource of Archival Breast Tissue population, including 35% Black women. Cases were diagnosed with DCIS from 1999-2019 with SBEs, including invasive breast cancer or ipsilateral or contralateral local DCIS. Controls matched 1:1 were diagnosed with DCIS from 1999-2019 without SBEs during similar follow-up times. The mean age at DCIS diagnosis was 56.3. The mean follow-up was 147.8 months. Principal Component Analyses (PCA) of 19,821 protein-coding genes were conducted on 141 DCIS samples, with >20 million total reads. PC1, representing 9.0% of the variation, was significantly correlated with race. PC3, representing 4.03% of the variance, correlated with follow-up time. We detected enrichment for interleukin and PD-1 pathways but no significant differentially expressed genes (DEGs) by case-control status. We identified significant DEGs with age, follow-up time, grade, race, and invasive SBEs. Generating high-quality RNA-seq data is feasible and elucidates novel insights on DEGs in diverse DCIS samples. Citation Format: Emma Berdan, Thomas Walsh, Sarah A. Lyons Humble, Jen Tappenden, Katherine DeSchryver, Deborah Veis, Kiran Vij, Shannan Ho Sui, Graham A. Colditz, Aditi Hazra. RNA-sequencing data in diverse women diagnosed with ductal carcinoma in situ [abstract]. In: Proceedings of the San Antonio Breast Cancer Symposium 2024; 2024 Dec 10-13; San Antonio, TX. Philadelphia (PA): AACR; Clin Cancer Res 2025;31(12 Suppl):Abstract nr P1-03-05.