Scientists have mapped all possible mutations in a key region of the CTNNB1 gene that controls the cancer-related protein β-catenin. Normally, this region tells the cell to break down β-catenin, but mutations allow it to build up and drive tumor growth.
Using genome-editing tools in mouse stem cells, researchers tested 342 different mutations and found that their effects vary widely—from weak to very strong activation of cancer-promoting pathways. They also discovered that different tissues prefer different mutation strengths; for example, liver cancers with stronger mutations had fewer immune cells, which may make them less responsive to immunotherapy.
The results closely matched genetic data from thousands of cancer patients, showing the map is reliable. This work could help doctors better predict how specific mutations affect cancer behavior and guide more personalized treatment decisions.