EXPRESSION OF THE EV11 GENE IN CHRONIC MYELOGENOUS LEUKEMIA IN BLAST CRISIS

The EVI1 gene encodes a nuclear, zinc finger, DNA binding protein expr essed after provirus insertion into the Fim-3 or EVI1 loci in murine l eukemia myeloid cells (1,2). EVI1 is also expressed by cells from AML patients with chromosome rearrangements involving band 3q26, the putat ive location of the EVI1 gene, but expression of this gene is not dete cted in normal bone marrow (3-5). We report expression of EVI1 by cell s from a patient with chronic myelogenous leukemia in blast crisis (CM L/BC) whose cells showed inv(3)(q22q26). In vitro culture of these cel ls resulted in macrophage differentiation and loss of EVI1 expression. Results in this patient suggest EVI1 expression played a role in CML blast transformation. Patients with CML/BC and other nonrandom chromos ome abnormalities involving chromosome 3q26 should be evaluated for EV I1 expression.