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 mutational burden, indicating enhanced tumor proliferation and aggressiveness.

• Why it matters: Understanding how ESR1 mutations influence protein signaling pathways is crucial for improving clinical outcomes and developing targeted therapies for resistant breast cancers.
• What they did: Researchers analyzed transcriptomic, proteomic, and phosphoproteomic data from tumors with ESR1 mutations, and validated findings using breast cancer cell line datasets, developing a predictive signature for recurrence risk.
• The result: Findings suggest ESR1 mutations are associated with ER-driven amplification of oncogenic pathways, and the predictive signature may help identify high-risk patients, informing personalized treatment strategies.