Brain Immune Cells Drive Cancer Spread Through Inflammatory Pathway

This groundbreaking research reveals how brain immune cells paradoxically help cancer spread rather than defend against it, with implications for multiple neurological diseases. Scientists studied brain metastases and found that immune cells called microglia and macrophages express high levels of CD74, a receptor protein previously thought to mainly present antigens to other immune cells.

The research team analyzed brain tissue samples from cancer patients and conducted laboratory experiments to understand CD74's role. They discovered that proliferating cancer cells produce large amounts of MIF (macrophage migration inhibitory factor), which binds to CD74 receptors on brain immune cells. This binding triggers the receptor to move into the cell nucleus, where it activates inflammatory pathways that actually promote cancer growth.

Crucially, patients with higher CD74 signatures in their brain metastases had more aggressive disease progression, while their original tumors showed no such correlation. The researchers also identified this same CD74 pathway in Alzheimer's disease and multiple sclerosis, suggesting a common mechanism across brain disorders.

The most promising finding involved ibudilast, an existing brain-penetrant drug that blocks MIF from binding to CD74. In laboratory studies, this drug successfully reduced brain metastases, offering immediate therapeutic potential. This discovery could revolutionize treatment approaches for brain cancers and potentially other neurological conditions by targeting the inflammatory environment that fuels disease progression rather than just the diseased cells themselves.