A constitutive estrogen stimulation in breast cancer cells enhances stronger ERα activity and further recruits its distal regulatory machinery including different coregulators, mediators, cohesions and chromatin remodelers, and then mobilizes highly dynamic gene looping events which essentially expand to render a 3D genome recompartmentalization accompanied with lower CTCF binding at the compartment boundary. Here, ESR1 is linked to breast carcinoma.