Only very recently has tamoxifen, a drug used successfully against breast cancer cells, been demonstrated to inhibit differentiation of quiescent PSCs into myofibroblasts via the G protein-coupled estrogen receptor (GPER)- and hypoxia-inducible factor-1 alpha (HIF-1α)-mediated mechanism and suppress matrix remodeling (Cortes et al., 2019a, b). This evidence concerns the gene HIF1A and breast cancer.