Abstract A030: Tumor-associated calcium signal transducer 2 is consistently upregulated in colorectal cancer in people of African ancestry

Abstract Colorectal cancer (CRC) is the third most diagnosed cancer worldwide and the leading cause of cancer-related mortality. Despite advancements in detection and therapy, current diagnostic and treatment strategies are primarily based on evidence derived from limited cohorts, which are then applied to a diverse and genetically heterogeneous global population, often resulting in suboptimal outcomes. This one-size-fits-all model overlooks individual variability in genetic, environmental, and lifestyle factors, which have a significant impact on disease progression, therapeutic response, and overall prognosis. Disparities in incidence, progression, and treatment outcomes may arise from population-specific variations in gene expression. We investigated gene expression profiles of tumor and adjacent non-tumor tissues from people in Ibadan, Nigeria, West Africa, using transcriptomics analysis of bulk RNA sequencing data. Differentially expressed genes (DEGs) were defined by a log2 fold change (log2FC) ≥ 1.0 for upregulated genes and ≤ -1.0 for downregulated genes, with a false discovery rate (FDR) adjusted p-value < 0.05 using the Benjamini–Hochberg correction. We compared DEGs to publicly available CRC bulk RNA sequencing datasets retrieved from the NCBI-GEO database and The Cancer Genome Atlas (TCGA) database. We identified 148 upregulated and 1,769 downregulated DEGs in CRC tumor samples from the Ibadan cohort. Comparative analysis revealed substantial variation in DEG profiles across populations, with many DEGs being unique to specific datasets and no single DEG consistently shared among all datasets. Notably, individuals of African ancestry exhibited distinct DEG signatures across datasets. Among these, the tumor-associated calcium signal transducer 2 (TACSTD2) gene was the only DEG consistently upregulated across all datasets, highlighting its potential relevance in CRC among individuals of African ancestry. Citation Format: Seidu Adams, Aiden Amin, Rachel Bonacci, Udekwu Chinedum, Oluwabusola Ajagbe, Maya Wilson, Dimitri Joseph Brian Thiesen, Ellen Li, David Irabor, Akinfemi Akingboye, Olorunseun O. Ogunwobi. Tumor-associated calcium signal transducer 2 is consistently upregulated in colorectal cancer in people of African ancestry [abstract]. In: Proceedings of the 18th AACR Conference on the Science of Cancer Health Disparities; 2025 Sep 18-21; Baltimore, MD. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2025;34(9 Suppl):Abstract nr A030.