Siglec-7 is a member of Siglec family of glycan recognition proteins involved in the regulation of natural killer (NK) cell activities. We found Siglec-7 ligand is highly expressed on JVM-3, a B cell chronic lymphocytic leukemia (B-CLL) cell line. In this experiment, we attempted at identifying the ligands of Siglec-7 on JVM-3 by applying the proximity labeling method we developed (Chang L et al., J Proteome Res. 2017, 16:3929-41).