Clinical Features and Prognosis in Childhood Acute Plymphoblastic Leukemia with TEL/AML1,BCR/ABL,E2A/PBX1 and MLL/AF4 Positive

Objective To explore the expression and clinical significance of TEL/AML1,BCR/ABL，E2A/PBX1 and MLL/AF4 fusion gene in childhood acute lymphoblastic leukemia(ALL). Methods Bone marrow samples were collected from 312 children with newly diagnosed ALL，and E2A/PBX1，BCR/ABLp190(e1a2)and p210(b2a3,b3a2) isoforms，TEL/AML1 and MLL/AF4 fusion gene were detected by RQ-PCR.Meanwhile，Clinico-biological characteristic，therapeutic response and outcome were retrospectively analyzed. Results （1） The fusion genes were positive in 120 ALL children.72 cases(23.1%) expressed TEL/AML1，22 cases(7.1%) expressed BCR-ABL(including 16 cases(5.1%)p190 and 6 cases(1.9%) p210，18 cases(5.8%) expressed E2A/PBX1 and 8 cases(2.6%) expressed MLL/AF4).（2） In TEL/AML1 positive children，the leukocyte count was(18.02±6.45)×109/L with a 100% complete remission(CR) rate and none relapsed during follow-up.In BCR/ABL positive children，the mean age was(9.40±3.55) years old with 81.8% CR rate.6 cases still expressed the fusion gene at the end of intensive treatment.8 children relapsed and 8 children died during follow-up.In E2A/PBX1 positive children，all of them were given chemotherapy according to high risk standard.The CR rate was 88.9%.Three cases expressed micro-content fusion gene at the end of intensive treatment.2 cases relapsed during follow-up.In MLL/AF4 positive children，the leukocyte count was(41.53±9.46)×109/L.2 cases still expressed the fusion gene at the end of intensive treatment，and both of them relapsed and died. Conclusion Fusion genes are important indexes for risk stratification,MRD monitoring and prognosis estimation in children with ALL.