Bcl-2 and activated caspase protein level in H-520 cells after treatment with ES and 4Gy irradiation were detected by a flow cytometry. A) Decreased Bcl-2 expression in ES and radiation-treated H-520 cells. B) Increased activated caspase level in H-520 cells induced by ES and irradiation. Data were presented as mean ± SD(N = 4). One representative of four identical experiments was shown.