ESR1 and breast cancer: Around the same time as the above findings were published, BRD7 was identified as an interacting partner of BRCA1, another tumor suppressor associated with breast cancer, [23]; this interaction recruits BRCA1 and Oct1 to the Esr1 promoter, which encodes estrogen receptor α (ERα) and in turn increases acetylation of histone H3 (Figure 3B) [23].