Multifaceted role of the vitamin B6 pathway in cancer: metabolism, immune interaction, and temporal and spatial regulation

Vitamin B6 is a metabolic cofactor that underpins critical regulatory pathways, including amino acid flux, one-carbon pathways, redox homeostasis, and neurotransmitter biosynthesis. Emerging evidence suggests that vitamin B6 deficiency or its metabolic dysregulation perturbs these core metabolic pathways, driving oncogenic programs in both solid tumors and hematologic malignancies. Moreover, vitamin B6-dependent processes can modulate several tumorigenic processes, such as proliferation, oncogenic signaling, immune regulation, and adaptive metabolic reprogramming. The tumor-specific spatiotemporal dynamics of vitamin B6 metabolism uncover context-dependent metabolic vulnerabilities that are tightly regulated by cellular state and tumor niche. This review addresses emerging mechanistic insights into the multifaceted functions of vitamin B6 in tumorigenesis. Furthermore, it proposes dynamic vitamin B6 metabolism as a promising therapeutic axis, offering novel opportunities for tumor-specific targeted intervention.