PI3K inhibitors induce apoptosis in CLL B cells. CLL cell viability was determined 24, 48, and 72 hours after addition of the PI3K inhibitors that are displayed on the vertical axis by staining with DiOC₆ and PI. The results represent the mean (± SEM; n = 7) relative viability of PI3K inhibitor treated CLL B cells compared with untreated controls (100%). The strongest cytotoxic effects at 1 μM and 10 μM were obtained with PIK-90 and PI-103, whereas TGX115 and IC87114 were found to be less potent. *Significant decrease in viability (P < .05).