Clinical characteristics and prognostic of 8 cases of acute myeloid leukemia patients with MLL-AF-6 fusion gene

Objective To investigate the clinical characteristics and prognostic of acute myeloid leukemia (AML) patients with MLL-AF-6 fusion gene.Methods Samples from eight acute myeloid leukemia patients with MLL-AF-6 fusion gene hospitalized in Department of Hematology of Anhui Provincial Hospital were collected.The correlation between clinical features,immunophenotype,rate of complete remission after the first induction therapy,overall survival,response to allo-HSCT or prognosis of patients and the dynamic change of MLL-AF6 fusion gene which was accessed by multiplex nested reverse transcription-polymerase chain reaction was.Results From February 2009 to August 2013,472 patients were diagnosed as acute leukemia (AL),including 285 AML patients,and eight of them with MLL-AF-6 fusion gene,who were account for 1.69 ％ (8/472) of AL and 2.80 ％ (8/285) of AML.According to WHO classification,all MLL-AF6 fusion gene-positive patients were classified into M1 (1 case),M2 (2 cases),M4 (2 cases),M5 (3 cases),in which M4/M5 were accounted for 62.50 ％ (5/8).After first induction therapy,the complete response (CR) and overall survival (OS) rated of AML patients with MLL-AF6 were 62.50 ％ (5/8) and 50.0 ％ (4/8),respectively.At the end of first course therpy,two of four patients receiving chemotherapy alone had negative detection of MLL-AF-6 fusion gene.During the follow-up period,one of them achieved hematologic complete remission and survived for 26 months,and the other had recurrence six months after diagnosis and died after treatment.The other 2 patients receiving chemotherapy alone had no change in MLL-AF6 fusion gene expression,who didn 't achieve hematologic complete remission and died finally.Four patients received bone marrow transplantation at the end of first course.Three of them became MLL-AF6 fusion gene negative and achieved hematologic complete remission,and survived with mean survival 28 months.One patient who received bone marrow transplantation did not become MLL-AF6 fusion gene negative and died after transplantation.Conclusions There is high incidence of MLL-AF6 fusion gene rearrangement in M4/M5 patients,which is often accompanied with hyperleukocytosis,organ infiltration,worse therapeutic effects,high recurrence rate and poor prognosis.HSCT is a reasonable treatment to improve the prognosis of those patients.Monitor the changes of MLL-AF6 fusion gene during the treatment can help to indicate the prognosis of patients. Key words: Leukemia, myeloid, acute;  MLL-AF-6 fusion gene;  Hematopoietic stem cell transplantion