Molecular analysis of a case of Philadelphia chromosome-positive acute myeloid leukemia

This report describes a precise molecular analysis of a rare case of Philadelphia chromosome (Ph) positive acute myeloid leukemia (AML) (FAB classification M2). Phenotypic markers were positive for cells of the myeloid lineage, but negative for B cell and T cell lineage. The leukemic cells carried a Philadelphia chromosome. Major breakpoint cluster region (M-BCR) rearrangement was detected by the Southern blot analysis. Reverse transcriptase polymerase chain reaction analysis revealed the presence of b3a2 BCR/ABL mRNA transcripts. The patient achieved complete remission by conventional remission induction therapy for acute myeloid leukemia. M-BCR rearrangement could not be detected during complete remission. After hematological remission of an 8-month duration, the patient relapsed and died of respiratory distress due to pneumonia. Our case indicate Ph-positive AML with M-BCR rearrangement actually exists. Ph-positive AML carries either M-BCR rearrangement expressing the P210 BCR-ABL or minor breakpoint cluster region (m-BCR) rearrangement producing the P190 BCR-ABL. Therefore, additional other factor (s) apart from the Ph chromosome must be responsible for the acute malignant transformation.