Some of the most lethal cancers in existence — small cell lung cancer, small cell prostate cancer, and related neuroendocrine tumors — have something in common: they almost universally lose a protective gene called RB, and they have resisted new therapeutic approaches for decades. A study from UCLA Health has now identified a hidden vulnerability in these tumors that may open a new treatment path, and existing FDA-approved drugs may already be positioned to exploit it.
The research, published March 20, 2026, in Proceedings of the National Academy of Sciences, found that when RB is lost, these cancer cells become critically dependent on a protein called E2F3 for survival. Block E2F3, and the cancer cells cannot survive — a mechanism scientists call "synthetic lethality."
