ERBB2 and breast cancer: Globally, based on the current knowledge, several published investigations support the idea that the CD44high/CD24low and ALDH1+ stem cell-like phenotypes can be used to identify BCSCs with distinct levels of differentiation; the former profile is more related to basal-like BC (basal/HER2), while the latter reflects HER2-overexpressing tumors originating from luminal progenitors (luminal/HER2) [22].