ESR1 and breast cancer: Given the known role of ER transcription factor in inducing 3D chromatin interactions in ER+ breast cancer cells7,24–26 and methylation-sensitive binding27, we profiled ER binding site (ERBS) patterns genome-wide in vehicle-treated (n = 4) and decitabine-treated (n = 4) tumors using ER ChIP-seq (Supplementary Note and Supplementary Table 4) to determine whether ER binding was specifically altered by DNA hypomethylation.