ESR1 and neoplasm: There were no significant differences in the baseline characteristics of the two groups in regard to mean age (p = 0.62), tumour size (p = 0.25), tumor grade (p = 0.27), tumour histology (p = 0.43), positive axillary lymph nodes (p = 0.35), ER positive status (0.35), Her2 positive status (p = 0.75), and use of neoadjuvant chemotherapy (p = 0.72) (Table 1).