A selective ALDH1A3 inhibitor, a quinazolin-4-amine derivative (Figure 4, Table 3), was recently reported by Kamiyama et al. to possess potent inhibitory activity in both enzymatic (IC50 = 0.0640 μM on the recombinant enzyme) and AldefluorTM assays in breast cancer MDA-MB231 cells [103,104]. Here, ALDH1A3 is linked to breast cancer.