FLT4 Receptor Tyrosine Kinase Gene Mapping to Chromosome Band 5q35 in Relation to the t(2;5), t(5;6), and t(3;5) Translocations

FLT4 is a recently cloned receptor tyrosine kinase cDNA, which is characterized by seven immunoglobulin‐like loops in its extracellular domain. We have previously mapped the FLT4 gene to chromosome segment 5q33‐qter using somatic cell hybrids. Here we have refined the localization to band 5q35 by fluorescence in situ hybridization and show that the gene is translocated to chromosomes 2 and 6 in the t(2;5)(p23;q35) and t(5;6)(q35;p21) translocations, respectively, of Ki‐1‐positive lymphomas, as well as to chromosome 3 in the t(3;5)(q25.1;q34) translocation, which is occasionally found in myelodysplastic syndromes and acute myeloid leukemia. No evidence was obtained for a rearrangement or deregulation of the translocated FLT4 gene. We further show that abundant FLT4 mRNA expression occurs only in erythroid and megakaryoblastoid cell lines among nine leukemia cell lines studied. © 1993 Wiley‐Liss, Inc.