Correlation of expression of HOXA9 and of selected mixed-lineage leukemia-specific genes with 11q23 copy number status. The geometric averages of the normalized expression of the different genes in the different patient groups (“Results”); group A (▪), group B (), and group C (□). P values indicate the significance of the difference in observed expression in 2-by-2 analyses of the different patient groups, as identified by the Mann-Whitney test. Significant P values are indicated in bold.