In addition, using microarray technology, it was demonstrated that the MLL-rearrangement cells present an upregulation of HOX genes (HOXA9, HOXA10, and HOXC6, together with the MEIS1 HOX cofactor), emphasizing the central role of deregulation of this class of genes in the pathogenesis of MLL-rearrangement ALL [20]. The gene discussed is MEIS1; the disease is acute lymphoblastic leukemia.