Gene expression profiles of bone marrow samples from patients with ALL, MLL, and AML. Each column represents a bone marrow sample and each row corresponds to a gene. The top marker genes for each diagnosis are shown. Shades of red indicate elevated expression while shades of blue indicate decreased expression. FLT3 is the gene that correlates most highly with the MLL leukemia subtype. Reprinted from Armstrong et al²⁴  with permission.