Abstract 7285: Gene expression-based subtypes associated with prognosis in Colombian colorectal cancer

Abstract In Colombia, colorectal cancer (CRC) is the fifth leading cause of cancer-related death. Molecular alterations linked to clinical-pathological variables are useful for prognosis and guiding treatment. However, current gene expression-based classifications have been developed mostly in non-Latin American populations, leaving Latin Americans underrepresented. To date, no gene expression studies have been conducted in Colombian CRC patients. Objective: Identify and characterize gene expression profiles and evaluate their association with the prognosis in Colombian patients with CRC. Methodology: FFPE tumor (n=35) and non-tumor (n=17) samples from CRC patients treated at the National Cancer Institute, Bogotá-Colombia between 2010-2014 were analyzed by RNA-seq. Differential gene expression was assessed with DESeq2 (FDR-adjusted ≤0.05, lfc of 2 and p-value ≤0.05)K-means, NFM and clusGap were used to clustering. Functional enrichment was performed using the ClusterProfiler and KEEG. WGCNA identified hub genes. Differences in the presentation of clinical-pathological variables were evaluated with chi-square and Fisher's tests (p0.05 considered statistically significant). Recurrence-free survival (RFS), metastasis-free survival (MFS), and overall survival (OS) were estimated by Kaplan-Meier method and the log-rank test. Results: From 1642 differentially expressed genes in tumor samples, 3 clusters were identified. Cluster 1, enriched in protein folding/translation pathways, was associated with more advanced disease p-value=0.019) and Right-sided tumors(p-value=0.026). Cluster 2(DNA replication, mitotic nuclear division, chromosome organization and chromatid segregation pathways), as a possible proliferative subtype, with all cases in early stages (I-III:100%) and predominantly left-sided tumors (76.9%). Cluster 3(metabolic and oxidative response pathways), showed shortest RFS (p=0.026), while Cluster 1 had a shortest MFS follow by Cluster 3p=0.005). No statistically significant differences were observed in OS. 19 Hub genes associated with CRC progression were identified (including TMEM150A, HNF1A, SNTB1, CLOCK, CCND1, ITGA2). Conclusions and perspectives: This first transcriptomic profiling of Colombian CRC patients reveals potential molecular subtypes associated with prognosis. These findings highlight potential biomarkers for personalized management and underscore the importance of including Latin American populations in CRC molecular studies to improve global equity in cancer care. Citation Format: Wendy Johana Montero Ovalle, Diego Felipe Ballen-Lozano, Liliana López-Kleine, Silvia Juliana Serrano-Gomez. Gene expression-based subtypes associated with prognosis in Colombian colorectal cancer abstract. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl):Abstract nr 7285.