FLT3-ligand enhances survival and increases sensitivity to CEP-701 in responsive FLT3/PM and FLT3/WT leukemic blasts. 48-hour MTT assays were performed with CEP-701 on selected samples both in standard culture medium (–FL) and in culture medium supplemented with 100 ng/mL of human FL (+FL). The mean OD (percent of untreated controls) is shown for each sample, grouped by CEP-701 responsiveness. Error bars represent the mean of the group ± SEM. The change in mean OD is noted next to the arrows. Patient numbers (from Tables 1, 2 and 3) are noted for each sample (P = FLT3/PM, W = FLT3/WT).