| Objective:To investigate the changes of PTEN gene expression and promoter methylation status in Acute leukemia(AL) patients,as well as explore their role in the development of AL and the relationship that exists between them,which provide the basis of molecular biology to fully understand the pathogenesis of AL,and also provide corresponding laboratory data for further diagnosis and targeted therapy of AL.Methods:Collected 42 cases of AL patients with newly diagnosed in February 2008～March 2009 as disease group,of which 20 cases were male,22 cases were female.The median age is 40 years old,ranging from 7 to 80 years old.42 cases include:acute myeloblastic leukemia(AML) 23 cases(M1 1 cases,M2 7 cases,M3 6 cases,M4 5 cases,M5 2 cases,M6 2 cases),acute lymphoblastic leukemia(ALL) 17 cases,1 case of acute plasma cell leukemia,1 case of acute biphenotypic leukemia. 23 cases bone marrow of patients with hematopoietic system non-malignant tumor as a control group.We used RT-PCR and MSP technology to research the mRNA expression level and promoter methylation of PTEN gene in bone marrow mononuclear cells of AL patients.The results were statistically analyzed using SPSS11.5 software package.Result:1,The results of PTEN gene expression in AL patients showed that:①42 cases of newly diagnosed AL patients.16 cases positive for PTEN gene expression,the positive rate was 38.1%;23 cases of the control group.21 cases were positive for PTEN gene expression,the positive rate was 91.3%.AL·group compared with the control group have significant difference(P＜0.05).②The positive rates of PTEN gene expression in AML and ALL group were 34.8%and 35.3%,which is lower than the control group,AML and ALL group to part compared with the control group,the differences both have statistically significance(P＜0.05);AML group compared with ALL group,the difference was no statistically significance(P＞0.05).③Comparing PTEN gene expression positive rate of≥14 years old and＜14 years old AL patients,and also compared with the positive rate of PTEN gene expression in male and female patients,there was no statistically significant difference(P＞0.05); Comparing PTEN gene expression positive rate of peripheral blood white blood cell count≥20×10~9/L and＜20×10~9/L of AL patients,also compared with the positive rate of PTEN gene expression in patients with extramedullary infiltration and with no extramedullary infiltration,and the differences have statistically significance(P＜0.05).The relevance analysis have shown that the relationship of PTEN gene expression positive rate and peripheral blood white blood cell count and extramedullary infiltration was a negative correlation(r=-0.355 and -0.381,P＜0.05).2,The study results of PTEN gene promoter methylation status in AL patients showed that:①in the 42 cases of newly diagnosed AL patients,10 cases were detected for the PTEN gene promoter methylation positive and methylation positive rate was 23.0%;23 cases of control group,there was no detectable PTEN gene promoter methylation,methylation positive rate was 0.0%.AL group compared with the control group,the difference was significant(P＜0.05).②AML and ALL groups PTEN gene promoter methylation rates were 17.4%and 35.3%,ALL group compared with the control group,the differences were statistical significance(P＜0.05);AML group compared with the control group,the difference have no statistical significance(P＞0.05);AML compared with ALL groups,the difference was not significant(P＞0.05).③We compared the PTEN gene promoter methylation rate of age≥14 years old and＜14 years old patients with AL,and also compared the PTEN gene promoter methylation rate of male and female patients with AL,there is no statistically significant difference(P＞0.05);We compared PTEN gene promoter methylation of AL patients with peripheral blood white blood cell count≥20× 10~9/L and＜20×10~9/L,and also compared the rate of extramedullary infiltration and no extramedullary infiltration in AL patients,the differences have statistical significance(P＜0.05).The relevance study have shown that PTEN gene promoter methylation positive rate and peripheral blood white blood cell count or extramedullary infiltration was positively correlated(r=0.362 and 0.395,P＜0.05).3,Comparison of age≥14 years old and＜14 years old PTEN gene expression in patients with AL positive rate,AL Comparison of male and female gene expression in patients with PTEN positive rate,there was no statistically significant differences;comparison of peripheral blood white blood cell count≥20×10~9/L and＜20×10~9/L of the AL gene expression in patients with PTEN-positive rate, compared extramedullary infiltration and extramedullary infiltration of the AL gene expression in patients with PTEN-positive rate,the differences were statistically significant.3,The results on the relationship of PTEN gene expression and promoter methylation in AL patients have shown:26 cases of PTEN mRNA negative expression was detected in AL group,and only 10 cases with PTEN gene promoter methylation,and all of the methylated specimens with the negative expression of PTEN mRNA.Statistical analysis showed that the relationship of PTEN gene promoter methylation status and PTEN gene expression was negatively correlated in AL patients,r was-0.439,P＜0.05.5,AML and ALL groups PTEN gene promoter methvlation rates were 17.4%and 35.3%,ALL group and the control group compared to the differences were statistically significant;AML group and the control group compared to the difference was not statistically significant.Conclusion:1,There is PTEN mRNA expression deletion in AL patients with, and PTEN expression deletion is existent in the AML and ALL at the same time,the relationship of PTEN mRNA expression and peripheral blood white blood cell count or extramedullary infiltration was a negative correlation,suggesting that loss of PTEN expression is the mechanisms of occurrence and development of AL.2.The PTEN promoter methylation rate in AL patients was significantly higher than control group,PTEN gene promoter methylation plays a certain role in the occurrence and development of AL,and such a role in ALL is affirmative,but in AML is still not affirmed and need to expand the sample size for further study.At the same time,PTEN gene promoter CpG island methylation and abnormal white blood cell count in peripheral blood or extramedullary infiltration was positively correlated.3,PTEN gene promoter methylation and expression of PTEN mRNA have the significant negative correlation in AL patients,but the PTEN gene promoter methylation are not the only mechanism which led to the inactivation of PTEN gene. There are other mechanisms involved in the reason of PTEN gene deletion,and the specific mechanisms need further study.4,In this study,from gene expression and DNA methylation studies of both PTEN gene occurred in the AL,the role of development and to explore their relationship may exist between,for comprehensive understanding of the pathogenesis of AL to provide a certain amount of experimental room data,and for further diagnosis of AL,the monitoring of minimal residual disease and targeted therapy to provide the basis for the corresponding. |
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