Figure 4

Apoptosis in EM-3 cells 24 h after start of incubation as detected by the annexin V/propidium iodide assay. Compared to treatment with imatinib alone or γ-irradiation alone (A, imatinib; B, γ-irradiation) a striking increase in the early apoptotic (lower right quadrant: annexin V+/PI−) and dead cell (upper right quadrant: annexin V+/PI+) fractions was observed (C) when the cells were treated with the combination. D, untreated cells.