Characterization of the dasatinib response of primary CLL cells. CLL patient cells were incubated in growth medium without or with 5 μM dasatinib for 48 hours and subsequently analyzed for annexin V–binding by flow cytometry. The dasatinib-induced decreases in the percentages of annexin V–negative, viable cells relative to untreated controls are below or above 26% in the left or right diagrams, respectively. For reference the cell lines JVM-3 and Mec1 are indicated in gray in the right diagram. Numbers to the left of the graphs belong to dotted lines, those to the right to solid lines, and refer to the patient information in Table 1 (A). Correlation of IgV_H mutation status (left) and ZAP-70 expression (right) with apoptosis induction by 5 μM dasatinib in primary CLL patient cells. Boxes with solid lines indicate the range from minimum to maximum responses; dashed and solid horizontal lines the medians and means, respectively, and error bars the standard deviations of the means (B). Apoptosis induction in primary CLL cells from 17 patients by 5 μM dasatinib, 5 μM fludarabine and a combination of both (C). Influence of coculture with the bone marrow stroma cell line HS5 on drug sensitivity (D). Error bars represent SD.