应用二代测序技术分析急性髓系白血病患者基因突变及其对预后的影响

Using next generation sequencing technology to analyze gene mutations in patients with acute myeloid leukemia and the impact on prognosis

目的应用二代测序技术(NGS)分析急性髓系白血病(AML)患者的突变基因谱,讨论基因突变在疾病预后分层中的价值。方法分析2014年1月1日到2017年12月31日间在上海7家综合性医院血液科收治的新诊断的AML(除外急性早幼粒细胞白血病)患者的临床资料。抽取患者的骨髓液,提取RNA和DNA后,应用白血病融合基因和髓系相关基因突变组套进行检测。分析白血病融合基因和基因突变检测结果,比较不同年龄组和不同染色体核型组的患者情况。Kaplan-Meier曲线用于患者生存分析。结果共纳入453例初诊AML患者,男女比例1.2∶1,中位年龄49.5(11~85)岁。其中289例患者共检测到了540个突变/融合基因,132例(29.1%)患者存在2个及以上的突变/融合基因。发生频率在10%以上的突变/融合基因有:NPM1突变12.8%,ETO 11.92%,TET2突变11.04%,以及WT1过表达者占10.6%。50岁以上的患者发生与表观遗传修饰相关的基因突变频率较高,ASXL111.93%,DMNT3A 13.99%,IDH1/IDH26.58%,TET213.17%。其中DMNT3A突变发生频率是50岁以下患者的3倍以上(P=0.017)。本研究中,低危核型组患者基因突变发生比例低。中危核型组中,NPM1、TET2、FLT3-ITD、DNMT3A、ASXL1、CEBPA双突变等都有较高的发生频率。高危核型组中ASXL1、TET2、DNMT3A、PHF6突变发生频率在10%以上,其中ASXL1和PHF6突变率明显高于低危和中危核型组(P<0.05)。正常核型AML(NK-AML)患者254例(占56%),其中伴有表观遗传修饰相关基因突变的患者56例,该组患者中位总生存期(OS)较无相关基因突变组患者短,中位无白血病生存期(LFS)差异无统计学意义。年龄大于50岁且有表观遗传修饰基因突变的NK-AML患者,其中位OS 12个月,中位LFS 10个月,而无相关基因突变的患者中位OS和LFS分别为18个月和12个月。结论不同年龄组和不同核型分组的AML患者基因突变发生频率有差异。>50岁的AML患者表观遗传修饰基因发生突变的频率高于≤50岁者。年龄>50岁且伴表观遗传修饰基因突变者总生存期短,预后差。

Objective To analyze the distribution of gene mutations in newly diagnosed acute myeloid leukemia(AML)patients,based on next generation sequencing technology(NGS)and to evaluate their value in AML risk stratification.Methods The study analyzed 453 newly diagnosed AML(excluded acute promyelocytic leukemia,APL)patients from seven hospitals in Shanghai,from January 1st 2014 to December 31th 2017.RNA and DNA were extracted from pretreatment bone marrow mononuclear cells and targeted sequencing of AML genes were performed.The data of different groups was compared.Results A total of 453 newly diagnosed AML patients were enrolled in the study,including 247 males and 206 females with a median age of 49.5(range,11-85)years.A total of 540 mutations/fusion genes were detected in 289 patients,29.1%(132/259)of whom with two or more mutations/fusion genes.In all patients,NPM1 was the most common mutation(12.8%),followed by ETO and TET2 mutation(11.92% and 11.04%,respectively).And WT1 over-expression accounted for 10.6%.Patients over the age of 50 were with a higher frequency of mutations associated with epigenetic modification,11.93%for ASXL1,13.99% for DMNT3A,6.58% for IDH1/IDH2,and 13.17% for TET2.The frequency of DMNT3A mutations was three times higher than that of patients under 50 years of age(P=0.017).In this study,a relatively low proportion of genetic mutations was observed in low-risk karyotype group.In the medium-risk karyotype group,the relatively high mutation frequencies were observed in NPM1,TET2,FLT3-ITD,DNMT3A,ASXL1,and CEBPA genes.In the poor-risk karyotype group,the mutation frequencies of ASXL1,TET2,DNMT3A and PHF6 genes were more than 10%,especially ASXL1 and PHF6 mutation frequencies were significantly higher than other molecular risk stratification groups(P<0.05).Of the 254 patients(56%)with normal karyotype AML(NK-AML),56 patients were detected to have gene mutations about epigenetic modification.The median OS of this group was worse than that of patients without related mutations,while the median LFS had no significant difference.In patients with NK-AML older than 50 years,the OS and LFS of patients with epigenetic modification related gene mutations was 12 months and 10 months,versus 18 months and 12 months of patients without mutations.Conclusions The gene mutations frequencies in AML patients with different age and molecular risk stratification groups are different.Epigenetics gene mutation frequencies,such as DNMT3A,ASXL1,IDH1/IDH2 and TET2,are higher in patients older than 50 years.A shorter OS can be observed in older patients(>50 years)with epigenetics gene mutation.