CHROMOSOMAL ABNORMALITY INV(3)(Q21Q26) ASSOCIATED WITH MULTILINEAGE HEMATOPOIETIC PROGENITOR CELLS IN HEMATOPOIETIC MALIGNANCIES

We have identified ten patients with acute myeloid leukemia (AML) and one patient with chronic myeloid leukemia with megakaryocytic crisis w ho displayed an inv(3)(q21q26). Seven of them had an additional monoso my 7. Most of them had a myelodysplastic syndrome (MDS) preceding AML, normal or increased platelet counts, increased number of megakaryocyt e, megakaryocytic dysplasia, and erythroid dysplasia. There was a high incidence of resistance to induction chemotherapy, short remission ti me, and early relapse. Seven patients were immunologically analyzed. T he main immunophenotypes were as follows: CD7+, CD34+, HLA-DR+, CD38+, CD13+, CD33+, CDw65+, CD2-, CD3-, CD4-, CD8-, CD19+, CD20-, CD11b-. O ur results suggest that the leukemia with inv(3)(q21q26) represents a new cytogenetic-clinicopathologic subtype, characterized by I) abnorma l megakaryopoiesis and multiple hematopoietic lineage involvement; 2) an antecedent MDS; 3) poor response to conventional chemotherapy; and 4) expression of CD7, CD34, CD38, HLA-DR, CD13, and CD33 antigens. We propose that the malignant transformation in patients with inv(3)(q21q 26) occurs in an early stem cell prior to lineage commitment. (C) Else vier Science Inc., 1997.