ESR1 and neoplasm: High ESR1 expression was associated with lower pCR rates (OR 0.73, 95% CI 0.65–0.82, p < 0.0001) in univariate analysis, even in the subgroup of patients with luminal tumours (OR 0.60, 95% CI 0.40–0.91, p = 0.0149), but not in multivariate analysis (data not shown).