ESR1 mutations are associated with enhanced MTORC1 signaling in a context-dependent manner.

ESR1 mutations in breast cancer are linked to increased MTORC1 signaling and higher tumor proliferation, indicating enhanced oncogenic activity.

• Why it matters: Understanding how ESR1 mutations influence signaling pathways is crucial for improving treatment strategies and predicting clinical outcomes in breast cancer patients.
• What they did: The study analyzed transcriptomic, proteomic, and phosphoproteomic data from tumors with ESR1 mutations, along with validation using breast cancer cell lines, to identify pathway alterations and develop a predictive signature.
• The result: Findings reveal that ESR1 mutations promote tumor aggressiveness through MTORC1 activation, enabling better risk stratification and highlighting potential targets for therapy.