Dendrogram and color matrix representing the hierarchic clustering of the 88 myeloma samples versus 61 genes. The genes used in this analysis were chosen by a discriminating score statistic that is most highly correlated with the 2 IgH isotypes. Blue-colored branches represent BJ-MM, red branches represent IgA-MM, and black branches represent IgG-MM. Columns represent individual MM samples, and rows represent individual genes on the microarray. 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. Gray indicates excluded values.