Hierarchic clustering of IgH-secreting MM based on the identified genes (49 members) that best distinguished IgG-MM from IgA-MM. Red-colored branches represent IgA-MM, and black branches represent IgG-MM. Genes were grouped in potential functional categories. Each column represents an MM sample, and each row represents an individual gene. A pseudocolor representation of gene expression is shown according to the scale at the bottom; red indicates expression levels greater than the median, and green indicates levels less than the median. Gene accession numbers, discriminating scores, and gene symbols are labeled on the right. Gray indicates excluded values.