EVI-1 EXPRESSION IN LEUKEMIC PATIENTS WITH REARRANGEMENTS OF THE 3Q25-Q28 CHROMOSOMAL REGION

The Evi-zinc-finger protein gene is normally not expressed in hematopoietic cells. However, high Evi-1 mRNA expression has been reported in mouse myeloblastic leukemias, due to transcriptional activation by proviral integration in either the Fim-3 or Evi-1 loci. The human Evi-1 gene is located on chromosome 3q24-q28. In this paper three examples are presented of human acute myelogenous leukemias presenting common characteristics: (i) high Evi-1 mRNA expression; (ii) chromosomal abnormalities t(3;3)(q21;q26) or inv(3;3)(q21-22;q26); and (iii) high platelet counts and dystrophic megakaryocytes. Thirty-four other patients with hematological malignancies, among which 11 had chromosomal rearrangements in the 3q24-q28 region did not exhibit such abnormalities. Of the 13 permanent hemopoietic cell lines tested, Evi-1 RNA expression was found in HEL and K-562 cell lines. Weak Evi-1 expression was also seen in fibroblasts and lung cells. This expression was affected neither in skin cells from a patient with a 3q27 constitutional translocation nor in a lung epithelioma cell line containing an excess of chromosome 3 long arm. Ectopic strong expression of Evi-1 in human leukemias could define an uncommon subclass of acute myelogenous leukemias with translocations involving the 3q25-28 chromosomal domain and abnormal megakaryopoiesis.