Finer delineation and transcript map of the 7q31 locus deleted in myeloid neoplasms

Acquired complete and partial deletions of chromosome 7 are associated with several malignancies. In acute myelogenous leukemia (AML) and preleukemic myelodysplasia (MDS), loss of chromosome 7 portends a poor clinical outcome. The identity of a classical leukemia suppressor gene, however, has been elusive. Previously, we defined a candidate suppressor locus of approximately 6 Mb in the 7q31 interval. Here we report an island of retention of heterozygosity within this interval in a case of monosomy 7. Allelotyping of AML cell lines revealed that ML3 and HEL cells, karyotypically diploid for chromosome 7, are hemizygous for all the 7q31 loci, implicating loss of the wild type and duplication of the remaining chromosome 7. Based on the completed genomic sequence of chromosome 7, we have generated a transcript map of the critical region of loss (between the D7S525 and D7S2502 loci). Notably, a recently characterized tumor suppressor gene, DOCK4, and an evolutionarily conserved zinc finger gene, ZNF277, localize to this interval, head to head, within <0.5 kb of each other. Thus, the reagents generated in this study will be valuable in elucidating the role of loss of 7q31 loci in the pathogenesis of AML.