IL6 and breast cancer: Intriguingly, STAT3, AKT, integrin β1 and Bcl-3 are linked to the activities of CSCs or embryonal stem cells [20,21,22,23], while CAF-CM and IL-6 are able to upregulate the RNA level of the CSC marker ALDH1A1 [18,19] and while IL-6 has the potential to increase CSC activity in breast cancer cells [24].