Resistance to therapies for ER+ breast cancer and enhanced survival of disseminated MCF7 cells stably expressing GIV recapitulate key features of MCF7 cells in co-culture with MSCs that we reported previously (19, 21), and future studies will delineate whether and how GIV alone may impact additional reported phenotypes, i.e., metabolic plasticity (20). Here, ESR1 is linked to breast cancer.