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

Abstract

To the clinical characteristics and prognostic value of the patients with complete deletion of TET_JBP domain (ΔJBP) in TET2 acute myeloid leukemia (AML). 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. 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 in ΔJBP group were older (63 vs 54 years old, P=0.047), and the occurrence rate of CEBPA double mutation (CEBPAdm) 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 <50×109/L (P=0.004) and CEBPAdm (P=0.001) were related to the shorter OS of the patients. Further COX multivariate analysis showed that CEBPAdm is an independent prognostic factors of OS in TET2ΔJBP patients (P=0.010). In addition, ΔJBP patients with CEBPAdm showed lower hemoglobin levels (62 vs 75g/L, P=0.030) and lower median OS (9 months vs 18 months, P=0.000) than the patients without CEBPAdm. 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 CEBPAdm, which is the independent prognostic factors of OS in AML patients with TET2ΔJBP.