ALDH1A1 and breast cancer: Liu et al. [39] found that increased ALDH1A1 activity in breast cancer led to expansion of myeloid-derived suppressor cells and immunosuppression, and also found that the ALDH1A1 inhibitor disulfiram and the chemotherapeutic agent gemcitabine synergistically inhibited breast tumor growth and tumorigenesis by clearing ALDH + tumor-initiating cells and activating T-cell immunity.