ESR1 and breast cancer: A cohort on 153 LM from BC (ER+ 51%, HER2+ 20.3%, and TNBC 15.0%) displayed that TNBC and ER positive patients had significant benefit in OS from intrathecal therapy (HR 0.60, 95%CI 0.37–0.97) and systemic therapy (HR 0.17, 95% CI 0.10–0.29) in multivariable analysis [8].