Fucosylation Dynamics as a Critical Determinant of Cancer Cell Fate in Colorectal Carcinoma: Integrating Hallmark Plasticity, Microenvironmental Remodelling, and Therapeutic Resistance

Fucosylation, the enzymatic addition of fucose residues to glycans, modulates receptor signalling and cellular identity in the intestinal epithelium. Its role as an integrative determinant of cancer cell fate in colorectal cancer (CRC) remains undefined. Transcriptomic and clinicopathological data from 976 CRC patients across three independent cohorts (TCGA-CRC, CPTAC2-CRC, Sidra-LUMC) were analysed. A curated fucosylation gene set was used to calculate tumour fucosylation scores. Associations with histogenetic status, genomic features, microenvironmental phenotypes, drug resistance programmes, and survival were evaluated using gene set enrichment analysis, multivariable Cox regression, and integrated molecular subtyping. High-fucosylation tumours exhibited elevated epithelial differentiation, MSI-H/BRAF-mutant enrichment, oxidative phosphorylation dominance, the complete absence of EMT and invasion programmes, and favourable prognosis (HR = 0.633, 95% CI: 0.470–0.853, p = 0.003). Low-fucosylation tumours demonstrated mesenchymal phenotypes, TP53 mutations, chromosomal instability, comprehensive multi-family RTK signalling, immune-excluded microenvironments, and poor outcomes. Distinct multidrug resistance programmes emerged: drug efflux in low-fucosylation tumours versus xenobiotic sensing, target bypass, and drug sequestration in high-fucosylation tumours. Tumour fucosylation status defines two fundamentally distinct CRC cell states with mutually exclusive engagement of invasion programmes, metabolic pathways, immune phenotypes, and resistance mechanisms. Fucosylation represents an independent prognostic biomarker and integrative determinant of cancer cell fate, with significant implications for risk stratification and personalised therapeutic strategies.