QPCR validation of discriminating genes. The bar graph depicts the real-time PCR analysis of transcript levels for CCND1, CD27, PSMA2, and SDF-1 in 15 AL, 10 MM, and 6 healthy controls. The y-axis shows the ratio of specific transcript expression to a housekeeping gene, β-actin. As seen with the micro-array analysis, gene expression levels for CCND1 are highest in AL PCs compared to MM and normal PCs. For CD27 and SDF-1, gene expression is higher in AL PCs compared to MM, but lower than in normal PCs. PSMA2 gene expression is higher in MM PCs compared to AL and normal PCs. Error bars indicate standard deviation.