Figure 2.

Rates of two types of cells generating stem-like spheres and differences in radiation sensitivity between stem-like spheres and parental cells. A: Influence of irradiation dosage on cell sphere formation. Formation rates were increased at doses of 2, 4 and 6 Gy in the KYSE150 cell line and at doses of 2 and 4 Gy in the TE1 cell line (P < 0.05); B: The differences in sensitivity to radiation between cell spheres and adherent cells were compared in a clone formation assay. Cell spheres were also more radioresistant than parent cells (P < 0.05).