title: Chronic myelogenous leukemia with e13a3 (b2a3) type of BCR-ABL transcript having a DNA breakpoint between ABL exons a2 and a3.
abstract: We describe a patient with chronic myelogenous leukemia (CML), in whom the DNA breakpoint in the BCR-ABL fusion gene was determined to result in a rare e13a3 (b2a3) transcript. The breakpoint in BCR was intron 13, which was 30 bp downstream from exon 13, and the breakpoint in ABL was intron 2, and was 46 bp downstream from exon a2. This case conforms to the mechanism of DNA breakage occurring within ABL intron 2, but not at 5' to ABL exon a2. With our review of this case and the literature, it seems that CML with the BCR-a3 fusion product is associated with a low proportion of circulating immature cells, mild or lack of splenomegaly, slow progressiveness, rather resistance to IFN-alpha, and good response to imatinib mesylate. This is the first report of BCR-a3-type CML in which the exact DNA breakpoint was identified and located between exons a2 and a3 of the ABL gene.
authors.affiliation: Department of Hematology and Oncology, Research Institute for Radiation Biology and Medicine, Hiroshima University, Hiroshima, Japan.
authors.forename: Li-Gen
authors.initials: LG
authors.lastname: Liu
authors.forename: Hideo
authors.initials: H
authors.lastname: Tanaka
authors.forename: Kinro
authors.initials: K
authors.lastname: Ito
authors.forename: Taiichi
authors.initials: T
authors.lastname: Kyo
authors.forename: Takuo
authors.initials: T
authors.lastname: Ito
authors.forename: Akiro
authors.initials: A
authors.lastname: Kimura
mesh_terms: D019457:Chromosome Breakage; D018450:Disease Progression; D019008:Drug Resistance, Neoplasm; D005091:Exons; D016044:Fusion Proteins, bcr-abl / Q000235:genetics*; D016313:Genes, abl / Q000235:genetics*; D006801:Humans; D007438:Introns; D015464:Leukemia, Myelogenous, Chronic, BCR-ABL Positive / Q000235:genetics* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D009360:Neoplastic Cells, Circulating; D010641:Phenotype; D012333:RNA, Messenger; D012334:RNA, Neoplasm; D013163:Splenomegaly
chemical_list: D012333:RNA, Messenger; D012334:RNA, Neoplasm; D016044:Fusion Proteins, bcr-abl