ESR1 and breast cancer: Inflammatory-related peripheral cells measured in routine blood tests (such as neutrophils, lymphocytes, and platelets) and their derived indexes, including platelet-lymphocytes ratio, monocyte-lymphocyte ratio (MLR), NLR, and systemic immune-inflammation index (SII), are also independent prognostic biomarkers in localized BC, in the neo-adjuvant and adjuvant setting, as well as in metastatic BC.14,15 In a previous study, in a cohort of breast cancer undergoing upfront surgery, preoperative systemic inflammatory biomarkers were independent predictors of disease recurrence in ER+ HER2−.