JAM-C is upregulated on CD138^low/neg cells in BM of patients with MM. Representative FACS plots of surface CD138 expression on living human MM cells gated on CD45^–CD56⁺CD38^dim/+ cells in BM at (A) time of diagnosis (T0) and (B) x+1 relapse (T2). Representative graphical analysis (representative histograms) of JAM-C–expressing cells (count) in BM of patients with MM comparing CD138^high (red) and CD138^low/neg (blue) cells (gated on living CD45^–CD56⁺CD38^dim/+ cells) at T0 and T2. (C) Fold change in total numbers of JAM-C⁺ cells in BM of patients with MM (n = 17) divided into CD138^high and CD138^low/neg cells from T0 to T2 (Mann-Whitney U test; error bars indicate SD). The horizontal lines represent the mean. (D) Percentage of JAM-C⁺ cells in BM of patients with MM comparing CD138^high and CD138^low/neg populations at T0 and T2 (n = 17). Unpaired, two-tailed Student t tests were used. Error bars indicate SD. The horizontal lines represent the mean.