Philadelphia chromosome-positive chronic myeloid leukemia expressing p190(BCR-ABL).

We describe a case of Philadelphia chromosome-positive chronic myeloid leukemia (Ph-positive CML) expressing p190(BCR-ABL). Reverse transcription-polymerase chain reaction (RT-PCR) analysis of bone marrow cells showed a 472-bp band using primers specific for the p190(BCR-ABL) but not p210(BCR-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 p190(BCR-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.