In breast cancer, doxorubicin inducesdownregulation of the Wnt/β-cateninsignaling pathway, cell cycle arrest in the G0/G1 phase, an increasein reactive oxygen species levels, and cytotoxic effects. More recently, it has been described that inbreast CSCs, the STAT3 pathway plays a critical role in the conversionof non-CSCs into CSCs through the regulation of the expression ofthe OCT-4 gene. This evidence concerns the gene POU5F1 and breast carcinoma.