Estrogensignaling has dual roles in MECs and breast cancer cells; on one hand it has anoncogenic role by promoting proliferation of ER+ luminal breast cancercells, on the other hand it also has a tumor suppressor role by promoting MECdifferentiation and inhibiting metastasis of breast cancer cells (Chimge and Frenkel, 2013). This evidence concerns the gene ESR1 and neoplasm.