ALDH is a detoxifying enzyme whose function has been linked to cancer chemoresistance.23 Indeed, both ALDH1A3 mRNA and ALDH activity were significantly increased by pemetrexed treatment in the CSF-1Rpos cells, as shown by qRT-PCR and FACS, respectively (Figure 4e, lower panel and Supplementary Figure 3C), thus further supporting the chemoresistant properties of this cell sub-population. The gene discussed is ALDH1A3; the disease is cancer.