Clonally unrelated BCR-ABL-negative acute myeloblastic leukemia masquerading as blast crisis after busulphan and interferon therapy for BCR-ABL-positive chronic myeloid leukemia.
We report a patient with Philadelphia (Ph)-positive, BCR-ABL rearrangement positive, chronic myeloid leukemia (CML) with a prolonged chronic phase of 24 years who was first prescribed alpha-2 interferon 22 years after initial diagnosis. This therapy was tolerated poorly on account of thrombocytopenia, but an eventual major cytogenetic response was followed soon afterwards by transformation to terminal acute myeloid leukemia (AML). Cytogenetic studies indicated that the transformed myeloblasts were karyotypically normal and Ph negative. Although polymerase chain reaction (PCR) analysis of total leukemic mRNA remained BCR-ABL positive, other molecular studies, including Southern blotting and fluorescent in situ hybridization (FISH) analyses, showed that myeloblasts were BCR-ABL rearrangement negative. PCR-based clonality studies using an X-chromosome-linked restriction fragment polymorphism within the phosphoglycerate kinase gene (PGK1) further showed that the Ph-negative blast cells had a different clonal origin from the Ph-positive clone of chronic phase. We suggest that cases of underlying Ph-negative leukemic transformation in Ph-positive CML warrant further study and should be considered for trial of intensive remission induction therapy as appropriate for acute leukemia.
Department of Hematology, Canterbury Health Laboratories, Christchurch Hospital, New Zealand.
R
R
Manley
J
J
Cochrane
M
M
McDonald
S
S
Rigby
A
A
Moore
A
A
Kirk
S
S
Clarke
P E
PE
Crossen
C M
CM
Morris
W N
WN
Patton
D000208:Acute Disease; D000328:Adult; D001752:Blast Crisis / Q000175:diagnosis*; D001853:Bone Marrow / Q000473:pathology; D002066:Busulfan / Q000627:therapeutic use*; D003937:Diagnosis, Differential; D005260:Female; D016044:Fusion Proteins, bcr-abl / Q000235:genetics*; D015321:Gene Rearrangement; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D016898:Interferon-alpha / Q000627:therapeutic use*; D015464:Leukemia, Myelogenous, Chronic, BCR-ABL Positive / Q000097:blood / Q000235:genetics / Q000473:pathology / Q000628:therapy*; D010735:Phosphoglycerate Kinase / Q000235:genetics; D016133:Polymerase Chain Reaction; D012150:Polymorphism, Restriction Fragment Length; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014960:X Chromosome
D016898:Interferon-alpha; D016044:Fusion Proteins, bcr-abl; D010735:Phosphoglycerate Kinase; D002066:Busulfan