ATR and B-cell chronic lymphocytic leukemia: Further, there was no significant difference in total DOCK8 levels in the whole cell lysate protein fraction of MEC1-002 WT, MEC1-002 SIGLEC-6 KO, B-CLL and normal donor B cells (Fig. 5c), indicating that the higher membrane levels of DOCK8 observed in MEC1-002 WT and B-CLL cells was due to increased association of Siglec-6 with DOCK8.