Breast Cancer, HER2 Mutations, and Overcoming Drug Resistance

A recent study suggests that HER2-mutated breast cancer may develop resistance to drugs that inhibit the tyrosine kinase domain of HER2 through developing mutations in HER3, which enhance the dimerization between HER2 and HER3. The HER3 mutations augment signaling. This study supports a specific approach to overcoming mutant-HER3–mediated resistance.