ER-positive/PR-negative tumours were found to have more aggressive features than ER-positive/PR-positive BCs (Arpino et al. 2005) Moreover, meta-analysis by Shiino et al. (2022) revealed that in recurrent tumours the loss of ER or PR is associated with shorter overall survival compared with receptor-positive concordant groups. This evidence concerns the gene ESR1 and neoplasm.