The mutant motif creates a stronger binding site for TF members of the E2F family, promoting high expression levels of FOXA1. This gene works as a transcriptional pioneer factor in breast cancer, enhancing chromatin accessibility for estrogen receptor interaction to its genomic targets [80], and has been linked to decreased response to fulvestrant, an estrogen receptor antagonist [81, 82]. This evidence concerns the gene ESR1 and breast carcinoma.