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

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 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.

Conclusions: 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.