Cancer Research

Tumors Hijack the Brain's Nervous System to Suppress Your Immune Defenses

Researchers at Penn and Yale discovered that lung adenocarcinoma tumors actively recruit vagal sensory nerves, sending signals to the brainstem that ramp up sympathetic nervous system activity back in the tumor. This sympathetic output releases norepinephrine, which binds to beta-2 adrenergic receptors on alveolar macrophages, suppressing their ability to fight cancer. Blocking any step in this sensory-to-sympathetic circuit — genetically, pharmacologically, or chemogenetically — significantly reduced tumor growth in mice by unleashing immune responses. The findings reveal a previously unknown brain-tumor feedback loop and suggest that repurposing beta-blockers or targeting vagal nerve circuits could enhance cancer immunotherapy.