To determine if surface-expressed Siglec-6 tethers DOCK8 to the cell membrane in CLL cells, we evaluated DOCK8 protein levels in the membrane fraction of MEC1-002 WT, MEC1-002 SIGLEC-6 KO cells, Siglec-6+ primary B-CLL cells, and normal healthy donor (ND) B cells. Here, ATR is linked to B-cell chronic lymphocytic leukemia.