CD133+ cells are more resistant to chemotherapeutic agents. STA-ET-8.2 cells were FACS-sorted and CD133+ and CD133- fractions treated with increasing concentrations of (A) Doxorubicin (Doxo), (B) Etoposide (Etop), (C) Vincristine (Vinc) or (D) a combination of all three drugs at high (Doxo 10 μM; Etop 10 ug/ml; Vinc 100 ng/ml), medium (Doxo 2.5 μM; 20 Etop 2.5 ug/ml; Vinc 25 ng/ml) and low (Doxo 0.5 μM; Etop 0.5 ug/ml; Vinc5 ng/ml) concentrations. Viability was assessed by MTS assay after 96 hrs (*p < 0.05) and CD133+ cells displayed increased drug resistance. (E): CD133+ and CD133- TC-71 cells are equally sensitive to Doxo, Etop, and Vinc. (F): Western blot reveals no difference in apoptosis and drug resistance protein expression between unsorted and CD133-sorted STA-ET-8.2 cell fractions.