ABL1 and B-cell chronic lymphocytic leukemia: P-CRKL phosphorylation was not dependent on IgVH mutation status (Figure 6C), and the ABL-inhibitor imatinib mesylate (imatinib) reduced the phosphorylation of CRKL in a dose dependent manner (Figure 6D), and rapidly reversed the culture-induced shape-change of CLL cells: Time-lapse photomicroscopy showed that the imatinib-treated cells retracted their large F-actin-rich processes and reverted to a globular cell-shape with reappearance surface villi, with established effect within 10 minutes (Figure 7A).