CD133 expression in ESFT cell lines is highly variable. (A): Expression of CD133 in nine ESFT cell lines was examined by RT-PCR and western blot analysis. The variability of protein expression in ESFT cell lines correlates with transcript expression. (B): Immunofluorescent staining of CD133 in three ESFT cell lines shows wide variation in the frequency of CD133+ cells. (C): Flow cytometric analysis of ESFT cell lines confirms widely variable frequencies of CD133+ cells in established cultures. Primary FACS plots are shown in the left panel and summary data from three independent experiments is shown in the right panel for eight different ESFT cell lines.