Hierarchic clustering analysis (unsupervised) of gene expression in T-ALL. Partial view of the hierarchic tree of genes (rows) and samples (columns), with MLL-ENL⁺ T-ALL cases (lines highlighted in red). Gene expression levels are indicated by different shades of red (higher expression) and green (lower expression). The detailed view of the cluster of genes associated with MLL-ENL cases demonstrates the involvement of HOX genes and other transcription factors associated with hematopoietic differentiation.