 The study shows that breast cancer stem cells, BCSCs, exist in two distinct states, mesenchymalike and epithelialike, with different characteristics and gene expression profiles. These findings suggest that the plasticity of BCSCs allows them to transition between EMT and Metlike states, which endows these cells with the capacity for tissue invasion, dissemination and growth at metastatic sites. This article was authored by Su Linglu, Yang Tseong, Dong Wang and others.