Copy number analysis in de novo and therapy-related myeloproliferative neoplasms

Loss of chromosome 7 and del(7q) [-7/del(7q)] are recurring cytogenetic abnormalities in hematologic malignancies, including acute myeloid leukemia and therapy-related myeloid neoplasms, and associated with an adverse prognosis. We performed SNP array analysis on de novo and therapy-related myeloid neoplasms and identified a 2.17 Mb commonly deleted segment on chromosome band 7q22.1 containing CUX1, a gene encoding a homeodomain-containing transcription factor. Haploinsufficiency of the highly conserved ortholog, cut, led to hemocyte overgrowth and tumor formation in Drosophila melanogaster. Similarly, haploinsufficiency of CUX1 gave human hematopoietic cells a significant engraftment advantage upon transplantation into immunodeficient mice. These data identify CUX1 as a conserved, haploinsufficient tumor suppressor frequently deleted in myeloid neoplasms. We performed SNP-array analysis of 34 primary patient samples with de novo or therapy-related myeloid leukemia and one acute myeloid leukemia cell line, UoCM1. For patient samples, DNA was obtained from the white blood cells of bone marrow or peripheral blood leukemia specimens. Cytogenetic analysis revealed clonal -7/del(7q) in 17 of the cases.