Interestingly, several regulatory features appear to be enriched among GWAS-identified breast cancer risk loci, such as TF binding sites for ERα, FOXA1, GATA3, E2F1, and TCF7L2, but also H3K4Me1 histone marks as well as regions of open chromatin marked by DNAse I hypersensitivity sites (DHSSs) (Cowper-Sal lari et al., 2012; Michailidou et al., 2017). Here, ESR1 is linked to breast cancer.