TET2基因截短突变体ΔJBP在急性髓系白血病患者中的临床意义

Clinical Significance of Truncated Mutant ΔJBP of TET2 Gene in Patients with Acute Myeloid Leukemia

目的:探讨伴有TET2基因TET_JBP结构域完全缺失(ΔJBP)的急性髓系白血病(AML)患者的临床特征与预后价值。方法:应用高通量测序技术(NGS)检测与AML相关的34种基因(包括TET2基因)突变的情况,利用I-TASSER工具对TET2蛋白全长及TET_JBP结构缺失体进行蛋白质三级结构的预测。结果:38例伴TET2突变的AML患者中,发生截短突变者22例(57.9%),其中16例(72.7%)产生TET2ΔJBP截短突变体,蛋白质结构预测显示,TET_JBP结构域缺失导致TET2蛋白三级结构明显改变。与非ΔJBP组患者相比,ΔJBP组患者年龄更高(63 vs 54岁,P=0.047),CEBPA双突变(CEBPA^(dm))的发生频率更高(31.3%vs 0,P=0.009),诱导化疗后完全缓解(CR)率更低(37.5%vs 81.8%,P=0.008),中位无事件生存期(EFS)(5 vs 19个月,P=0.000)及中位总生存期(OS)更短(16 vs 22个月,P=0.041)。单因素分析表明,血小板<50×10^(9)/L(P=0.004)、伴有CEBPA^(dm) (P=0.001)与更短的OS相关,进一步COX多因素分析提示,CEBPA^(dm)是影响TET2ΔJBP患者OS的独立预后因素(P=0.003)。此外,伴有CEBPA^(dm)的ΔJBP患者较不伴CEBPA^(dm)者呈现更低的血红蛋白水平(62 vs 75 g/L,P=0.030)和更短的中位OS(9 vs 18个月,P=0.000)。结论:具有TET2ΔJBP截短突变体的AML患者诱导化疗后CR率较低、EFS和OS较短,可能与预后不良相关,易发生CEBPA^(dm)共突变,且后者是TET2ΔJBP突变AML患者OS的独立影响因素。

Objective: To the clinical characteristics and prognostic value of the patients with complete deletion of TET_JBP domain( ΔJBP) in TET2 acute myeloid leukemia( AML). Methods: Next Generation Sequencing technology was used to determine the mutations of 34 AML-related genes( including TET2 gene). The I-TASSER tool was used to predict the tertiary structure of the full-length TET2 protein and TET_JBP structure deletion. Results: Among 38 AML patients with TET2 mutations,22( 57. 9%) showed truncation mutations,of which 16( 72. 7%) produced TET2ΔJBP truncation mutants. Protein structure prediction showed that the deletion of TET JBP domain lead to the significant changes of tertiary structure in TET2 protein. Compared with the patients in non-ΔJBP group,the age of patients inΔJBP group were older( 63 vs 54 years old,P = 0. 047),and the occurrence rate of CEBPA double mutation( CEBPA^(dm)) were more frequency( 31. 3% vs 0,P = 0. 009),the complete remission( CR) rate after induction chemotherapy( 37. 5% vs 81. 8%,P = 0. 008) were lower,the median EFS( 5 vs 19 months,P = 0. 000) and median OS( 16 vs 22 months,P = 0. 041) were shorter. Univariate analysis showed that platelets < 50 × 10^(9)/L( P = 0. 004)and CEBPA^(dm)( P = 0. 001) were related to the shorter OS of the patients. Further COX multivariate analysis showed that CEBPA^(dm) is an independent prognostic factors of OS in TET2ΔJBP patients( P = 0. 010). In addition,ΔJBP patients with CEBPA^(dm) showed lower hemoglobin levels( 62 vs 75 g/L,P = 0. 030) and lower median OS( 9 months vs 18 months,P = 0. 000) than the patients without CEBPA^(dm). Conclusion: AML patients with TET2ΔJBP truncation mutant shows lower CR rate,shorter EFS and OS after induction chemotherapy,which may be related to the poor prognosis,and co-mutation with CEBPA^(dm),which is the independent prognostic factors of OS in AML patients with TET2ΔJBP.