To complement our scRNA-seq data findings at the chromatin level, we acquired ATAC-seq data for four distinct breast cancer (BC) epithelial cell lines: two triple-negative breast cancer (TNBC) cell lines (MDA-MB-231 and MDA-MB-436) with repetitions27, one estrogen receptor-positive BC cell line (MCF7) with repetitions28 and two normal MCF-10A breast epithelial cell lines29,30. This evidence concerns the gene ESR1 and breast cancer.