Abstract
Although numerous pathways are known to control the tumor suppressor protein p53, coordinated regulation of the p53-Notch axis by Numb may have an even more remarkable impact. In this issue, Colaluca at al. (2018. J. Cell Biol. https://doi.org/10.1083/jcb.201709092) reveal an unexpected role of a newly characterized Numb splice variant in the regulation of p53, which may have significant implications for therapeutic intervention in breast cancer.