ALDH positive CSC are endowed with stem cell properties. A: Representative ALDH cytometry from H460 unsorted cells grown in presence of 10% FCS-containing medium or stem cell medium. Percentage of ALDH+ cells in H460 cell line was increased when cultured in stem cell medium. B: Hematoxylin eosin staining of tumors engrafted after injection of ten thousand H460 ALDH sorted cells (40X). C: Tumor incidence and volume three weeks after cell injection. D: Isolation of both SP and non-SP cells present higher colony formation efficiency in soft agar than their negative counterpart. E: Q-RT-PCR analysis in sorted H1299 cells confirmed higher expression of ALDH and ABCG2 in ALDH+ cells. These cells also overexpress dyskerin, a component of telomerase subunit. Data and error bars are presented as mean ± SEM; *: p < 0.05, or as indicated.