急性髓系白血病TFPI-2基因表达及启动子甲基化的研究

本研究检测了组织因子途径抑制物-2（tissue factor pathway inhibitor-2,TFPI-2）基因在急性髓系白血病（acute myeloid leukemia,AML）患者骨髓单个核细胞中的表达水平及其甲基化状态,探讨其与AML发生、发展及危险度分层的关系.分离33例初治、19例完全缓解、12例复发/难治AML患者及15例单纯缺铁性贫血患者（对照组）骨髓单个核细胞,采用实时定量PCR （RT-PCR）检测TFPI-2 mRNA在其中的表达水平,采用甲基化特异性PCR （MSP）检测启动子CpG岛甲基化状态.结果表明,初治组、完全缓解组及复发/难治组TFPI-2 mRNA表达水平均低于对照组（P＜0.05）,复发/难治组TFPI-2 mRNA表达水平明显低于初治组（P =0.006）,与完全缓解组相比,初治组TFPI-2 mRNA表达水平也显著降低（P=0.030）;64例AML患者TFPI-2基因启动子甲基化频率为64.63％ （42/64）,其中初治组、完全缓解组和复发/难治组患者中TFPI-2基因启动子甲基化频率分别为66.67％（22/33）、52.63％ （10/19）和83.33％ （10/12） （P＞ 0.05）;甲基化AML患者与非甲基化AML患者骨髓单个核细胞中TFPI-2 mRNA的相对表达量分别为0.165（0.005-2.099）和0.597（0.011-2.787） （P ＜0.05）,在对照组骨髓单个核细胞中未检测到TFPI-2基因启动子的甲基化;初治组经2个疗程化疗后,完全缓解组（CR）骨髓单个核细胞TFPI-2 mRNA表达量显著高于未完全缓解组（PR＋ NR） （P=0.031）.结论：在AML中TFPI-2基因表达下调或沉默与启动子甲基化有关,TFPI-2基因表达水平及启动子甲基化状态可以作为AML分层及病情进展的指标.

Expression of TFPI-2 Gene and Its Promoter Methylation in Acute Myeloid LeukemiaExpression of TFPI-2 Gene and Its Promoter Methylation in Acute Myeloid Leukemia

The aim of this study was to detect the mRNA expression of tissue factor pathway inhibitor-2 （TFPI-2） and its methylation in bone marrow mononuclear cells from acute myeloid leukemia （AML） patients and to explore its significance in AML. Bone marrow mononuclear cells were isolated from newly diagnosed AML patients （ n = 33 ）, complete remission AML patients （n = 19 ）, relapsed/refractory AML patients （n = 12 ） and iron deficiency anemia patients （ control group, n = 15 ）. Expression of TFPI-2 mRNA was detected with real-time quantitative PCR （RT-PCR） and the methylation of CpG island in its promoter was detected with methylation-specific PCR （MSP）. The results showed that the expression of TFPI-2 mRNA in newly diagnosed AML, complete remission AML and relapsed/ refractory AML patients was much lower than that in the controls （P 〈 0.05）. Furthermore, its expression in relapsed/ refractory AML patients was lower than that in newly diagnosed AML patients （ P = 0.006）. Compared with complete remission AML patients, the expression of TFPI-2 mRNA in newly diagnosed AML patients was significantly reduced （P= 0. 030）. The percentage of TFPI-2 promoter methylation in AML patients was 64.63% （42/64）. In newly diagnosed AML group, complete remission AML group and relapsed/refractory AML group, the percentages of TFPI-2 promoter methylation were 66.67% （22/33）, 52.63% （ 10/19 ） and 83.33% （10/12） （ P 〉 0.05 ）, respectively. The optical density ratio of TFPI-2 mRNA expression was 0. 165（0. 005 - 2. 099） in methylated AML patients, and 0. 597 （0. 011 -2.787） in unmethylated AML patients（P 〈0.05）, Methylation of TFPI-2 gene promoter was not detected in control patients. After 2 courses of chemotherapy, the level of TFPI-2 mRNA was much higher in the CR group than that in the non-CR group（P 〈0.05 ）. It is concluded that the down-regulation or silence of TFPI-2 gene potentially results from its promoter methylation, and the expression level of