While plasma cell expression of SK1 was similar between healthy normal individuals, patients with monoclonal gammopathy of undetermined significance (MGUS) and myeloma, the expression of SK2 was significantly increased (P < 0.001, Kruskal-Wallis test) in myeloma patients compared with healthy normal age matched controls (Figure 1B). Here, SPHK2 is linked to plasma cell myeloma.