SNAI1 and breast cancer: (b) Although ectopic SNAI1 overexpression usually associates with stem-like features among mesenchymal breast cancer cells [12], its loss generates quasi-epithelial cells with the stem/progenitor phenotype, which causes retention of the stem-like features of the cells, based on preferential expression of a new set of stemness proteins (Fig. 5, Supplementary Fig. 3).