SOX2 and breast cancer: Taken together, these data suggest high correlation between IRISOE and high expression of the breast cancer stem cell biomarkers (e.g., CD44 and CD133) and the stemness-enforcers (e.g., Sox2, Oct4, Nanog and β-catenin) in locally advanced breast cancers, pre-clinical animal models, and in vitro although mechanism(s) responsible for that are still unknown.