BDNF and cancer: Disruption of this brain-to-liver signaling, as evidenced in cancer cachexia studies where vagal dysfunction depletes hepatic HNF4α - a master regulator of metabolism - highlights the importance of intact brain-liver communication in maintaining metabolic homeostasis (31).Within this bidirectional network, brain-derived neurotrophic factor (BDNF) functions as a significant modulator at the interface of neural and metabolic processes.