Microarray gene expression analysis in AL, MM, and normal PCs. Average gene expression levels for the 3 most discriminating genes (SDF-1, CD27, PSMA2) are shown for the 24 AL, 28 MM, and 6 healthy controls. In addition, gene expression levels for CCND1 are shown for these 3 groups. For SDF-1 and CD27, the average gene expression is higher in AL than MM PCs, but lower than normal PCs (SDF-1, AL = 544, MM = 264, NC = 602; CD27, AL = 716, MM = 340, NC = 909). For PSMA2, gene expression levels are higher in MM PCs compared to AL and normal PCs. CCND1 expression is the highest in AL PCs compared to MM and normal PCs. Error bars indicate standard deviation.