ESR1 and breast cancer: MCF-7-specific ERα-driven SEs indeed regulated genes with pivotal roles in breast cancer (e.g., BCAS3, as an amplified and overexpressed gene and ZNF217, the candidate organizer of repressive histone modifiers) (highlighted in blue in Supplementary Figure S7A) and altered the expression of genes regulated by Ishikawa-specific SEs, which were typically specific for endometrial cancer (e.g., ANXA2 and ATF4) (highlighted in red in Supplementary Figure S7B) [48,49,50,51].