Philadelphia chromosome-positive chronic myeloid leukemia expressing p190BCR-ABL

We describe a case of Philadelphia chromosome-positive chronic myeloid leukemia (Ph-positive CML) expressing p190BCR-ABL. Reverse transcription-polymerase chain reaction (RT-PCR) analysis of bone marrow cells showed a 472-bp band using primers specific for the p190BCR-ABL but not p210BCR-ABL transcript. Sequencing analysis revealed that the PCR product was derived from the fusion between BCR exon e1 and ABL exon a2 (e1a2). CML expressing p190BCR-ABL is relatively rare. In a review of the literature, it may be grouped into 2 categories; approximately half of the patients exhibited prominent monocytosis and intermediate hematological phenotype between CML and chronic myelomonocytic leukemia, and the remaining patients showed no monocytosis.(Internal Medicine 41: 1183-1187, 2002)