ESR1 and breast cancer: After LASSO-based dimension reduction, multivariate logistic regression confirmed that ER negativity (<i>p</i> = 0.039, OR = 15.079, 95% CI: 1.151-197.543) and HER-2 positivity (<i>p</i> = 0.044, OR = 0.014, 95% CI: 0.000-0.896) were independent predictors of higher pCR rates.<h4>Conclusion</h4>pCR rates in breast cancer patients post-NAC vary significantly by molecular subtype.