ESR1 and breast cancer: Consistent with the in silico results, we found highest expression levels of ZEB1 and BMP-inhibitors in the bone metastatic cell line MDA-BoM-1833 compared to the parental MDA-MB-231 and the lung metastatic MDA-LM2–4175, as well as to the luminal, ER positive breast cancer cell lines MCF7 and T47D, which expressed neither ZEB1 nor BMP-inhibitors (Fig. 2C).