Putting the brakes on an abundant growth-promoting protein causes breast tumors to regress, according to a study published in the Journal of Experimental Medicine. Triple-negative breast tumors lack all of the known growth receptors that serve as treatment targets in other types of breast cancer, making this the most clinically challenging subtype of the disease. Patients with these tumors tend to relapse earlier and have shorter disease-free survival.

Andrei Goga and colleagues now show that triple-negative breast tumors express elevated levels of the growth-driving protein called MYC. MYC activity was required for the growth of these aggressive tumors, and blocking a MYC-cooperating protein, CDK, caused triple-negative tumors to shrink in mice. Together, these results identify a potential new target for triple-negative tumor treatment.