Mapping of chromosome 17 breakpoints in acute myeloid leukemias

Abstract

The 17q11-21 chromosomal region is frequently involved in non-random structural rearrangements associated with the M1 and M2 subtypes of acute myeloid leukemias (AML), as well as with the 15;17 translocation typical of the promyelocytic subtype. A number of genes have been localized in this region including the c-erbA-1 and c-erbB-2 proto-oncogenes, the genes coding for the granulocyte-colony stimulating factor (G-CSF), the retinoic acid receptor alpha (RAR alpha) and the myeloperoxidase enzyme (MPO). However, the precise location of these genes in relationship to the 17q11-21 breakpoint(s) has not been determined. Using in situ hybridization on metaphase chromosomes, we established the position of the breakpoints in relationship to the c-erbA-1, c-erbB-2, G-CSF, RAR alpha and MPO loci in a series of AML cases bearing 17q11-21 rearrangements. We report: (i) that the respective position of the five genes is centromere - c-erbA-1 - G-CSF - c-erbB-2 - RAR alpha - MPO - telomere; (ii) that the breakpoints of the various AML subtypes are variably located between the centromere and c-erbB-2 in M1 and M2; (iii) that the breakpoints are consistently located between c-erbB-2 and RAR alpha/MPO in M3; and (iv) that the breakpoint on chromosome 17 in the 15;17 translocation is located on 17q21 and not on 17q11-12 as previously reported.