To investigate whether GR signaling impinges on ER+ breast cancer metastatic disease progression and animal survival, we used the clinically relevant metastatic and endocrine therapy-resistant (Jeselsohn et al, 2014; Toy et al, 2013) ESR1 mutant MCF-7 D538G and Y537S cells (Scott et al, 2017). This evidence concerns the gene ESR1 and breast cancer.