Strikingly, Carroll et al. demonstrated that 54% of estrogen receptor binding regions also contain Forkhead factor binding sites and that FOXA1 co-binding was necessary for ERalpha-mediated activation of estrogen receptor target genes on human chromosomes 21 and 22 in MCF-7 breast cancer cells stimulated by estrogen[53]. The gene discussed is ESR1; the disease is breast carcinoma.