The PRDM16 (1p36) gene is rearranged in acute myeloid leukaemia (AML) and myelodysplastic syndrome (MDS) with t(1;3)(p36;q21), sharing characteristics with AML and MDS with MECOM (3q26.2) translocations.
EVI1, located at chromosome band 3q26, encodes a 1051 amino acid zinc finger protein inappropriately expressed in the leukemic cells of 2-5% of acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS) patients.
Ecotropic viral integration site-1 (EVI1) and myelodysplastic syndrome 1 (MDS1) are located at the center of this region, and their DNA copy number increases are associated with at least 5-fold increased RNA transcript levels in 83% and 98% of advanced ovarian cancers, respectively.
Constitutive expression of Evi-1 in hematopoietic cells, which is caused by retroviral insertions or chromosomal translocations and inversions, is closely associated with myelogenous leukemias and myelodysplastic syndromes in mice and humans.
In summary, the results show that the defects in the erythroid development in a subpopulation of patients with myelodysplasia is localized at an early stage of the erythroid differentiation and is associated with the persistent expression of the CD34 antigen and, in some cases, with the expression of Evi-1.
In contrast to previous studies in AML and MDS, the pattern of EVI-1 expression suggests it may facilitate rather than inhibit myeloid differentiation during ATRA treatment.
This result suggests that the high incidence of Evi-1 expression which remains at low levels in RAEB and RAEBt is not a major determinant of ineffective erythropoiesis and myelopoiesis in MDS.
Whereas this interaction could provide the basis for the erythroid defects in EVI1-positive MDS, it does not explain the alteration of myeloid differentiation.