Honeth G et al. - The authors demonstrate an association between basal-like and particularly BRCA1 hereditary breast cancer and presence of CD44+/CD24- cells. However, not all basal-like and very few HER2+ tumors contain CD44+/CD24- cells, which emphasizes that a putative tumorigenic ability may not be confined to cells of this phenotype and that other breast cancer stem cell markers remain to be identified.