Protein Identified in Cancer Drug Resistance.

Researchers have identified a new role for MDM2, a known regulator of the tumor suppressor protein called p53, in shutting down cell death signals. The investigators found that resistance to the drug lapatinib (a tyrosine kinase inhibitor) in different types of breast cancer could be traced to high levels of MDM2, which promoted cell survival through a particular pathway. In a mouse model, an MDM2 inhibitor reduced the growth of tumors from lapatinib-resistant breast cancer cells. The Science Signaling findings suggest that other drugs targeting tyrosine kinases may also be vulnerable to resistance through this mechanism.