When assessing the potential useof ALDH1 to detect malignant mammary stem/progenitor cells in situ on breast cancer tissuesections, Ginestier et al. [23] found that ALDH1 expression correlatedwith the histoclinical parameters, suggesting the use of this marker as apowerful predictor of poor clinical outcome. The gene discussed is ALDH1A1; the disease is breast carcinoma.