Characterization of the 5q- breakpoint in an acute nonlymphocytic leukemia patient using pulsed-field gel electrophoresis

Abstract

Multiple genes of hematopoietic importance have been localized to the long arm of chromosome 5 including granulocyte‐macrophage colony stimulating factor (GM‐CSF) and interleukins (IL) 3, 4 and 5 to 5q23‐31, colony stimulating factor 1 (CSF1) to 5q33.1 and its receptor (c‐fms) to 5q33.3. The genes coding for platelet‐derived growth factor receptor (PDGFR) and acidic fibroblast growth factor (FGFA) have been localized to 5q31‐32 and 5q31.3‐33.2, respectively. These genes fall in the region of chromosome 5 which is deleted in the 5q‐ refractory anemia syndrome (5q‐ RA) and acute nonlymphocytic leukemia (ANLL). We have characterized this region in a 5q‐ patient with therapy‐related ANLL (t‐ANLL) by pulsed‐field gel electrophoresis and Southern blotting analysis utilizing DNA probes for PDGFR, c‐fms, and FGFA. A single 300 kbp MluI restriction fragment was detected in the patient using a PDGFR probe as compared to a 200 kbp fragment in normal controls. BssHII digestions also showed restriction fragment length difference. Similar data for both MluI and BssHII digestions were also obtained when c‐fms was used as a probe. Southern blotting analysis of EcoRI‐digested DNA showed that each of the PDGFR, c‐fms, and FGFA alleles were deleted. These results suggested that one chromosome 5 has a large deletion involving PDGFR, c‐fms and FGFA, which is consistent with the cytogenetic analysis of the patient. In contrast, the other chromosome 5, which appeared normal cytogenetically, may have a smaller deletion (or alteration) in proximity to but not involving any of these 3 genes.