OBJECTIVETo explore the clinical and laboratory characteristics in favor of the diagnosis of Ph/BCR-ABL positive acute myeloid leukemia (Ph/BCR-ABL⁺ AML).

METHODSRetrospectively analyzed the clinical and laboratory characteristics of 12 Ph/BCR-ABL⁺ AML cases from Feb, 2006 to Dec, 2013, with classic myeloid blast crisis of chronic myeloid leukemia (CML-MBC) as control, and followed-up the survival in these two cohorts of patients.

RESULTSThe median age of 12 Ph/BCR-ABL⁺ AML was 27.5 years, 10 cases (83.3%) showed non/mild splenomegaly, and mainly comprised of M₂ and M₄ subtypes according to FAB classification. The median number of basophils and megakaryocytes in peripheral blood and bone marrow was lower than that of CML-CBC patients. All the cases expressed myeloid antigens, 8 cases (66.7%) expressed CD34, 11 cases were detected with t(9;22), 5 cases (45.5%) with additional chromosomal abnormalities, including 1 case of inv(16). All the cases had BCR-ABL transcripts at diagnosis:3(25.0%) cases were e1a2 type and the remaining was b2a2/b3a2type, among which 1 case coexpressed CBFβ-MYH11. Two out of 6 cases existed AML-like mutations:1 case of CEBPA and the other of FLT3-TKD. For all the patients, 7 cases achieved complete remission (CR), including 6 out of 7 cases receiving induction chemotherapy combined with tyrosine kinase inhibitor (TKI) achieved CR, and 1 out of 3 cases receiving chemotherapy alone achieved CR. The median overall survival was 16.5 months, that of allo-HSCT group was 33.5 months, which was higher than that of non-HSCT group (5.5 months).

CONCLUSIONThe expression of e1a2 type BCR-ABL, the coexpression of fusion genes which were more common in AML, the existence of AML-like mutations were all indications of a de novo Ph/BCR-ABL⁺ AML. Low induction CR rate and short survival of Ph/BCR-ABL⁺ AML implied that chemotherapy combined with TKI and followed by allo-HSCT in CR was the only effective way to improve their survival.