A multi-omic analysis of EOCRC: Divergent methylation and gene expression signatures in young patients.

3582 Background: The incidence of early-onset colorectal cancer (EOCRC; diagnosis < 50 years) is rising at an alarming rate. EOCRC often exhibits distinct clinical features compared to late-onset colorectal cancer (LOCRC), yet the underlying mechanisms remain poorly understood. This study aimed to characterize a cohort of EOCRC patients by integrating DNA methylation, gene expression, and metabolomic profiles to identify age-specific molecular drivers. Methods: We performed an integrated multi-omic analysis on a cohort of 42 patients, comprising 16 EOCRC and 26 LOCRC cases that were collected from the Total Cancer Care at the Ohio State University. For each patient, fresh-frozen tumor tissue and paired adjacent normal tissue were analyzed using reduced representation bisulfite sequencing (RRBS). Parallel transcriptomic profiling was conducted by RNA-seq on all tumor samples. Additionally, systemic metabolic signatures were captured from plasma using liquid chromatography-mass spectrometry (LC-MS). Functional integration of differentially methylated regions (DMRs), gene expression signatures, and metabolomic profiles was performed using Ingenuity Pathway Analysis (IPA) to identify enriched canonical pathways. Results: Integrative analysis revealed a divergent molecular fingerprint in EOCRC compared to LOCRC. At the epigenomic and transcriptomic levels, EOCRC tumors demonstrated significant enrichment in neurotransmitter-related pathways, such as CREB signaling in neurons and ion channel transport, alongside a pronounced activation of G-protein coupled receptor (GPCR) signaling. Furthermore, we identified a distinct immune-related signature characterized by the activation of phagosome formation and S100 family signaling pathways. These intracellular alterations were mirrored by a unique systemic metabolic profile involving the G alpha signaling pathway and the transport of vitamins, nucleosides, bile salts, and amine compounds. In addition, we identified a multi-omic signature of 11 genes that exhibit both differential gene expression between EOCRC and LOCRC tumors and significant tumor-specific methylation drift relative to adjacent normal tissue. Notably, this signature is enriched with established epigenetic clock/aging markers, including LEP , PLA2G4F , CYP2E1 , GCM2 , ZNF418 , and MINAR1 , making them ideal candidates for early detection by liquid biopsies or risk-stratification tools for EOCRC. Conclusions: Our findings demonstrate that EOCRC is a biologically distinct entity driven by specific epigenetic and immune dysregulation. The simultaneous enrichment of neurotransmitter pathways and GPCR signaling suggests that EOCRC development may be uniquely influenced by neuro-epithelial interactions. The 11-gene signature enriched with epigenetic aging markers may serve as screening or surveillance tools for EOCRC patients.