Basal-like breast cancer is a particularly aggressive subtype of the malignancy, for which it has been difficult to identify good therapeutic targets. In collaboration, European researchers mined public transcriptome datasets to show that the aldehyde dehydrogenase 1A isoform ALDH1A3 was predominantly expressed in epithelial cells within basal-like tumors, whereas the isoforms ALDH1A1 and ALDH1A2 were predominantly expressed in stromal and immune-associated cells.