FACS-sorted CD133+ STA-ET-8.2 cells from spheres in non-adherent culture conditions. (A): STA-ET-8.2 cells were isolated by FACS using anti-CD133 antibody followed by plating at single cell dilution in 96 well plates. After 3-4 weeks in culture, individual spheres of > 50 cells (top image) were apparent in 11.4% of wells seed with a single CD133+ cell whereas sphere-forming efficiency from CD133- cells was only 2.3%. Results are the sum of 2 independent experiments using 192 wells/experiment. (B): Four individual CD133+ cell-derived spheres from (A) were collected and analyzed by flow cytometry. As shown, the percentage of CD133+ cells in the spheres ranged from 54-86% indicating that colonies derived from individual CD133+ STA-ET-8.2 cells contain both CD133+ and CD133- cells.