We placed the breast cancer patient tumor samples in four groups according to their ESR1 expression (up to or higher than quantile 0.65: 199.3 transcripts per million [TPM] for the TCGA Pan-Cancer Atlas patients and 11.3 normalized units for the METABRIC patients) and EERES (up to or higher than quantile 0.65: 0.219 for the TCGA Pan-Cancer Atlas patients and 0.185 for the METABRIC patients). This evidence concerns the gene ESR1 and neoplasm.