Vitamin A Pathway Found to Help Cancers Evade Immune Defenses

Scientists at Princeton University’s branch of the Ludwig Institute for Cancer Research have uncovered how a vitamin A–derived molecule allows cancers to escape immune attack. The research focuses on all-trans retinoic acid, which was found to weaken anti-tumor immune responses and reduce the effectiveness of dendritic cell–based cancer vaccines.

In two studies published in Nature Immunology and iScience, researchers showed that retinoic acid alters dendritic cells, shifting them toward immune tolerance rather than activating tumor-killing T cells. The process is driven by ALDH1A enzymes, which are frequently overexpressed in cancer cells and immune cells within tumors.

The team also developed an experimental compound, KyA33, that blocks retinoic acid signaling. In mouse models, the drug restored immune activity, improved vaccine performance, and slowed tumor growth. The findings help resolve long-standing contradictions about vitamin A and cancer and suggest a promising new direction for cancer immunotherapy.

20-01-2026