| Objective: Daxx (death domain associate protein), a kind of multifunction nucleoprotein, plays an important part in cell apoptosis, transcriptional control, viral infection and so on. E2F1 (E2 promoter binding factor-1), transcription factor, an important member of E2F family,plays a key point in the proceeding of cell cycle regulation and the process of cell multiplication, and cell multiplication could be stimulated by the over expression of E2F1. In this study we used the method of immunohistochemical streptavidin-perosidase (IHC, SP) to detect the expression of Daxx and E2F1 in bone marrow cell (BMC) of childhood acute leukemia (AL), and research their effect in the process of leukemia. It may provide a new way for childhood acute leukemia's mechanisms, a theoretical basis for the early diagnosis of AL and new targets for the prevention and treatment of early leukemia.Methods:1 Patients and groups: 40 children who were newly diagnosed with acute leukemia were collected in our hospital from June, 2008 to June, 2009, as experiment group. There were 23 patients with acute lymphoblastic leukemia (ALL), which includes 3 cases of L1 and 20 cases of L2 (with no L3 case); and 7 cases of high risk, 16 cases of standard risk. There were 17 patients with acute myeloblastic leukemia (AML) which includes 4 cases of M2 ,4 cases of M3 , 4 cases of M4 ,3 cases of M5 , 1 case of M6 and 1 case of M7 (no M1 case). The control group included 20 cases of non-malignant hematological disease children whose sex and age matched with experiment group.2 Samples collection and operating sequence: 0.2ml bone marrow were collected from all of the 40 patients with acute leukemia and 20 cases of non-malignant hematological disease children, after film preparation, they were all fixed by acetone of 4℃for 30 minutes, then preserve them in -20℃ for reserve. Daxx and E2F1 were all measured by SP.3 Statistic analysis: SPSS 13.0 was used to analysis the data. Analysis methods included chi square test (or Fisher exact propability) and correlation analysis.A P value of less than 0.05 was considered as significant.Results:1 The expression of Daxx in bone marrow cell1.1 The positive rate of Daxx protein in 40 acute leukemia patients(40%) was significantly higher than the rate of 20 control cases(10%) (χ2=5.71, P<0.05).1.2 The positive rate of Daxx protein in 17 AML patients(58.8%) was significantly higher than the rate of ALL cases(26.1%) (χ2=4.365, P<0.05).1.3 The positive rate of Daxx protein in ALL-L1(33.3%) and in ALL-L2 patients(25%) were basically the same, there was no significant difference between them(P=1,P>0.05).1.4 The positive rate of Daxx protein in ALL who were high risk(ALL-HR) patients(57.1%) was significantly higher than those standard risk (ALL-SR)cases(12.5%) (P=0.045,P<0.05). The positive rate of Daxx protein in ALL-HR group was significantly higer than the rate of control group(10%) (P=0.024,P<0.05); and the difference between the rate of ALL-SR and control group was no significance (P=1,P>0.05).1.5 There were 17 patients with acute myeloblastic leukemia (AML). In all of the hypotypes group,Daxx expression cases were 3, 3, 2, 2, 0, 0 in turns. The rate was 75%, 75%, 50%, 66.67%, 0%, 0% in turns. For there was only 1 case in AML-M6 and 1 in AML- M7, make chi square test among the groups of M2, M3, M4, M5. the diference among them was no significance (P>0.05).1.6 The CR rate of the positive group(56.3%) was lower than the negative group(91.7%). The diference was significant (P<0.05).2 The expression of E2F1 in bone marrow cell2.1 The positive rate of E2F1 protein in 40 acute leukemia patients(57.5%) was significantly higher than in 20 control cases(20%) (χ2=7.576, P<0.05).2.2 The positive rate of E2F1 protein in AML(64.7%) and in ALL patients(52.2%) were basically the same, there was no significant difference between them(P=0.59, P>0.05).2.3 The positive rate of E2F1 protein in ALL-L1(33.3%) and in ALL-L2 patients(55%) were basically the same, there was no significant difference between them(P=0.59, P>0.05).2.4 There was no difference between the expression of E2F1 protein in ALL high risk(ALL-HR) patients(71.4%) and those stsndard risk (ALL-SR)cases(56.3%) (P=0.657,P>0.05). The positive rate of E2F1 protein in ALL-HR group and the rate of ALL-SR group were all significantly higer than the rate of control group(20%) (P<0.05).2.5 There were 17 patients with acute myeloblastic leukemia (AML). In all of the hypotype group,Daxx expression cases were 3, 3, 3, 2, 0, 0 in turns. The rate was 75%, 75%, 75%, 66.67%, 0%, 0% in turns. For there was only 1 case in AML- M6 and 1 in AML- M7, make chi square test among the group of M2, M3, M4, M5. The diference was no significance (P>0.05).2.6 the CR rate was not significant between the group of negative(69.6%) and positive(88.2%) (P>0.05).3 In 40 patients with acute leukemia, the expression of Daxx was positive correlated with the expression rate of E2F1,by the method of correlation analysis (χ2=14.339, P <0.05).Conclusions:1 High expression level of Daxx and E2F1 in childhood acute leukemia of newly diagnosed, it indicates that they could be used as a detective index.2 Daxx expression in AML was higher than in ALL, which indicates that Daxx is correlated with the classification of acute leukemia.The remission rate of negative group which expressed Daxx in AL was higher than the positive group. It indicates that Daxx may be an index of clinical prognostic in childhood AL.3 The experiment shows that Daxx and E2F1 are direct correlation. They were possibily cooperated in the process of childhood acute leukemia genesis and growth. |
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