“…These studies are based on the capacity of stem cell populations to efficiently efflux dyes such as Hoechst 33342. However, the toxicity associated with the Hoechst 33342 dye has precluded its use for the selection of cell popula-tions for functional stem cell assays in vivo (Balicki and Beaulieu, 2007). Due to the growing need for new markers to identify and isolate stem cells, assays based on ALDH activity have been proposed as a promising alternative.…”