B-CLL cell sensitivity to DSB-induced apoptosis. R indicates resistant B-CLL cells; and S, sensitive B-CLL cells. (A) Sensitivity of B-CLL cells to γ-irradiation-induced apoptosis (R: n = 13 samples; S: n = 79 samples). Sensitivity of R (n = 5 samples) and S (n = 15 samples) B-CLL cells to NCS-induced (B), VP16-induced (C), and okadaic acid-induced (D) apoptosis. Percentages of apoptotic cells are the means (± SEM) of duplicate experiments on B-CLL samples.