SOX2 and breast cancer: In line with this notion and verifying SOX2 as a functional downstream target of AKT in BC, overexpression of SOX2 was able to rescue sphere formation in AKT-inhibited cells, albeit the reduced size of the rescued spheres suggested that other AKT-dependent effects (e.g. induction of cell proliferation) might not be equally restored (see Supplementary Figure 5).