Clinical and laboratorial analysis for 15 adult cases of mixed phenotypic acute leukemia with Ph chromosome and/or positive BCR-ABL

Abstract

The purpose of this study was to summary the clinical and laboratorial features in 15 adult cases of mixed phenotypic acute leukemia with Ph chromosome and/or BCR-ABL fusion gene positive (Ph(+)MPAL), 15 adult patients with Ph(+)MPAL were defined by WHO-2008 classification. The clinical characteristics, results of morphology, immunology, cytogenetics and molecular genetic detections and results of follow-up in 15 adult patients with Ph(+)MPAL were analyzed retrospectively. The results showed that 15 patients among 87 cases of MPAL demonstrated Ph(+)MPAL (17.2%; 15/87) (7 males and 8 females), their median age was 51 (range 16-81) year old and median WBC count at diagnosis was 69 (12.7-921)×10(9)/L. Based on FAB criteria, these patients showed different morphologic types, including AML (13.3%; 2/15), ALL (40.0%; 6/15), HAL (46.7%; 7/15). Immunologic analysis indicated that 15 cases of Ph(-)MPAL were all classified as B-lymphoid +myeloid mixed immunophenotype. Except one patient, all expressed CD34 antigen on the surface of leukemia cells with 64.3% strong positive, only Ph (53.3%; 8/15), Ph with additional chromosomal abnormalities (33.3%; 5/15) and normal karyotype (13.3%; 2/15) were cytogenetically identified. BCR-ABL fusion gene transcript positive were detected by multiplex reverse transcription PCR in all cases, with e1a2 subtype (p190) (40.0%; 6/15) and b2a2 or b3a2 (p210) subtype (60.0%; 9/15). Four out of 7 (57.1%) patients were found to have IKZF1 gene deletion, without other common gene mutations. Seven out of 10 cases (70.0%) achieved complete remission (CR) after one cycle of induction chemotherapy. In the induction stage, CR rate seemed higher when tyrosine kinase inhibitors (TKI) were added to chemotherapy (83.3%:50.0%; P = 0.206). Overall survival (OS) in 4 patients received allogeneic hematopoietic stem cell transplantation (allo-HSCT) was longer than that in 4 patients received chemotherapy alone (P = 0.004). It is concluded that Ph(+)MPAL mainly is expressed as B+My phenotype. The majority of patients is older and has CD34 overexpression. In the aspect of molecular genetics, the Ph(+)MPAL is similar to other acute leukemia with Ph chromosome. Ph(+)MPAL is a subtype of acute leukemia with poor prognosis. WBC count at diagnosis is an independent prognostic factor. The combination of TKI and allo-HSCT can improve their long-term survival, which needs to be confirmed through carrying out a prospective and multicenter clinical trial for newly diagnosed Ph(+)MPAL.