Detection Of DNMT3A Mutation In Hematologic Malignancies And Its Clinical Significance

Objective:To investigate the incidence and distribution of DNMT3A mutation and explore the relationship between DNMT3A mutation and clinical characteristics, then to discuss its clinical significance in hematologic malignancies.Methods:A total of123patients with hematologic malignancies were randomly selected as research objects, who were inpatients of our hospital or Xiangtan Central Hospital from April2012to January2013. Genomic DNA was extracted from fresh peripheral blood, and a fragment covering the entire encoding region of exon23of DNMT3A gene was amplified by polymerase chain reaction (PCR) using primer pair which was designed for mutation hot spot ’R882site’ of DNMT3A gene, PCR products were purified and sequenced to investigate the incidence and distribution of DNMT3A mutation. The clinical and laboratory date, response to therapy and survival status of all the123patients were analyzed in order to discuss the clinical characteristics of hematologic malignancies with DNMT3A mutation and explore the clinical value of DNMT3A mutation.Results:(1) DNMT3A mutation was detected in8of63(12.7%) AML patients. The maximum incidence was found in AML M5, which was5of12(41.67%), and the percentage of M5in the patients with DNMT3A mutation was higher than the patients with wild DNMT3A (P=0.005). DNMT3A mutation was detected in1of5NHL patients, and the only one mutated NHL patient was the Precursor lymphoid neoplasms (T-lymphoblastic leukaemia/lymphoma) according to the2008World Health Organization proposal, which had not been reported before. DNMT3A mutation was absent in AHL、ALL、MDS、MM and MPN.(2) AML patients with DNMT3A mutation had higher white blood cell count in peripheral blood than the patients with wild DNMT3A (P=0.012), but there was no statistical significance in gender, age, hemoglobin level in peripheral blood, platelet count in peripheral blood and blast cells in bone marrow. Immunophenotype analysis showed that leukemia cells from patients with DNMT3A mutation usually expressed CD33, CD34, CD64, HLA-DR, CD13, CD7, CD14and expressed much higher CD14and CD7than that from patients with wild DNMT3A (P=0.031,.P=0.015). Patients with DNMT3A mutation always accompanied with positive NPM1mutation (P=0.045).(3) The AML patients with DNMT3A mutation had lower ratio of CR after the1st chemotherapy than the patients with wild DNMT3A (P=0.047); the patients with DNMT3A mutation had lower total ratio of CR and shorter PFS, but there were no statistical significance.Conclusions:(1) DNMT3A mutation occurred more frequently in AML, the incidence was12.7%, and was more commom in M5. DNMT3A mutation could also be detected in T-lymphoblastic leukaemia/lymphoma.(2) DNMT3A mutation was always associated with higher white blood cell count in peripheral blood, higher expression of CD14and lymphoid antigen CD7, and always accompanied with positive NPM1mutation in AML. It was unfavourable for DNMT3A mutated patients to reach CR through chemotherapy.(3) AML patients with DNMT3A mutation had a poor prognosis; The clinical significance in other hematologic malignancies, such as NHL, AHL and ALL, remained to be further studied with larger sample sizes.This article includes14tables,5figures and36references.