CD44 and cancer: Because NDRG1 pleiotropism is not only dependent on the cancer type but also the origin of tumor cells, we next evaluated whether NDRG1 driven by TGFβ1 could have a distinctive role in different types of CSCs populations, namely the chemoresistant, metastatic, and proliferative ALDH1+, the more quiescent, chemoresistant, and invasive CD44+/CD24-, and the drug-resistant side population 44-46.