中文摘要：

目的探讨miR-155在初诊急性髓系白血病（AML）患儿的骨髓单个核细胞中的表达情况，并分析其意义。方法从标本库抽取52例初诊AML患儿骨髓标本，进行总RNA抽提及miR-155特定的eDNA反转录，以30例非恶性病儿童骨髓作为对照。按照国家综合癌症网（NCCN）2013AML预后分组标准分为预后良好组、中等组和不良组。利用实时荧光定量聚合酶链反应（qRT-PCR）法检测miR-155的表达水平（以2-△△Ct表示）。结果miR-155在AML组显著高于对照组（Z=-5．391，P〈0．001）；miR-155在预后良好、中等和不良组之间差异有统计学意义（χ2=12．586，P=0．002），预后良好组呈低表达；在不同突变类型之间miR-155的表达水平差异亦有统计学意义（χ2=11．216，P=0．024），以FLT3-TKD基因突变组最低，FLT3-ITD基因突变组最高；在不同融合基因分组间差异有统计学意义（χ2=12．254，P=0．016），AML-ETO组最高，PML-RARa组最低；按法-美-英（FAB）分型后，各亚型间的miR-155表达水平差异有统计学意义（χ2=17．814，P=0．013），M3组较非M3组明显降低（Z=-3．291，P=0．001）。结论miR-155在初诊儿童AML中呈现非常显著的高表达现象，低水平的miR-155与良好预后相关。

英文摘要：

Objective To investigate the differential expression of miR - 155 in newly diagnosed pediatric a- cute myeloid leukemia（AML） and its clinical significances. Methods Fifty - two AML children and 30 non - malig- nant disease matched children were recruited as the controls. The preliminary AML children were divided into favorable group, moderate group and poor group according to the National Comprehensive Cancer Network（NCCN） 2013. Real - time quantitative polymerase chain reaction was applied to validate the expressions of miR - 155 in bone marrow sam- pies （the data presented by 2-△△Ct）. Results By comparing expressions of miR - 155 between AML patients and controls ,the miR - 155 expressions were significantly higher in the AML children than those in the controls （Z = -5.391, P 〈 0.001 ）. There were significant differences among different prognostic groups, with a significantly lower level in the favorable group compared with others （χ2 = 12. 586 ,P = 0.002 ）. It was also found that differential expressions existed not only in kinds of mutation cohort, with the highest level in FLT3 - ITD and the lowest one in FLT3 - TKD mutation group （χ2 = 11. 216,P =0. 024）, but also among fusion gene subgroups （χ2 = 12. 254, P = 0. 016）, with the highest level in AML- ETO group and the lowest level in PML- RARa group;meanwhile, the expressions of miR -155 were statistic different according to French -America- British（FAB） subtypes （χ2 = 17. 814 ,P =0. 013 ） ,which was lower in M3 patients than non - M3 patients （Z = - 3. 291, P = 0. 001 ）. Conclusions It indicates that the expressions of miR- 155 may increase sharply in preliminary AML children,and the lower expression of miR- 155 is closely related to favorable prognosis.