We were surprised to find the three proteins that most-distinguished myeloma plasma cells from B-ALL, based on fold-change and p-value, were not canonical markers at all: gamma-glutamyl transferase 1 (GGT1), selectin-P ligand (SELPLG), and cell adhesion molecule 1 (CADM1) (Fig. 1E). Here, SELPLG is linked to precursor B-cell acute lymphoblastic leukemia.