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.
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.
The EVI1 gene may be expressed through at least two pathways in hematologic malignancies; one is related to chromosomal changes at 3q26, while the other is related to myelodysplasia regardless of chromosomal changes at 3q26 region.
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.
Our results suggest that the leukemogenic role of EVI1 expression may differ between post-MDS AML and leukemia, with EVI1 expression associated with a 3q26 abnormality.
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.
EVI1 RNA was expressed in 29% of 34 (95% confidence interval, 20% to 50%) patients with the MDS subtypes refractory anemia (RA), refractory anemia with excess blasts (RAEB), or refractory anemia with excess blasts in transformation (RAEB-T).