A Study On DNMT3A Mutation And The Relationship Between Gene Mutations In Leukemia

Objective The purpose of this project is to detect DNMT3A mutation and clinical characteristics in patients with leukemia, to analyze the relationship between DNMT3A mutation and IDH1, IDH2, FLT3 gene mutation, and to find the correlation between gene mutations and its relation to the clinical data, providing new theoretical basis for the clinical diagnosis and treatment of AML and the improvement of prognosis.Method From 2013.4 to 2014.5, collect the leukemia patients’bone marrow samples and clinical data from the First Affiliated Hospital of Kunming Medical University; extract total genomic DNA for the collected specimens, use the PCR method to amplify the R882-inclusive fragments of No.23 exon in DNMT3A gene, the No.4 exon of gene IDH1, IDH2, and the No.11 exon of gene FLT3-ITD, and sequence and analyze their mutation.Result There are 4 cases (2.9%) having a mutation in the DNMT3A gene among 138 AML patients. In 41 newly diagnosed patients there is 1 case of AML DNMT3A mutations; the mutation rate is 2.44%; In 37 cases of recurrent and refractory patients there are 2 cases of mutations; the mutation rate is 5.41%; In 60 complete remission patients with AML were found 1 case of DNMT3A mutations; the mutation rate is 1.67%. All the cases are R882 heterozygous mutations, including two types of mutations (R882H (n=3) and R882C (n=1)). R882P and R882S mutations are not detected. In AML patients DNMT3A mutations are all distributed in the M5 parting; the mutation rate of 12.9%(4/31). Mutation is not found in other types of parting. Mutation rate was 12.12%(4/33) in NK-AML. The clinical parameters such as gender, age, white blood cell, hemoglobin concentration, platelet count, bone marrow primitive cells of the DNMT3A mutation group were not statistically different from the DNMT3A wide type group.Among ALL patients,2 cases were found of DNMT3A mutations in 8 recurrent and refractory patients; the mutation rate is 25%; 1 case for Ph+B-ALL patients,The other 1 for T-ALL patients;while in 16 newly diagnosed ALL patients and 15 ALL-CR patients mutation is not found. There is 1 case(2.4%) A884A synonymy mutations among the 43CML patients.16 cases of CLL patients mutation is not found.Among AML patients, DNMT3A mutation only concur in new and refractory patients with other mutations. Among the 41 new cases, there is one case of the concurrence of DNMT3A mutations with FLT3 mutations, but not with IDH1 or IDH2. Of the 37 recurrent and refractory cases of AML patients, there is 1 case of DNMT3A mutations concurring with DDH1 gene mutations, and not with FLT3, IDH2 gene mutations. Of the 39 cases of ALL patients,2 in 8 recurrent and refactory patients have DNMT3A mutations, both concurring with other mutations,1 with IDH1 gene mutations, and the other with IDH2 gene mutations.Conclusions 1. Among AML patients, all groups(new diagnosis, the recurrence and complete remission) have DNMT3A mutations, and the mutation rate conforms to a law(recurrence group> new diagnosis group> remission group),strongly suggesting that DNMT3A mutations may be as an index of recurrence.2. DNMT3A mutations occur in recurrent and refractory ALL patients; Ph+ patients with ALL of DNMT3A gene mutation, of which the mutation has not been reported before. Because of less number of cases, the gene mutation’s influence on the prognosis of patients with ALL needs further research.3. DNMT3A mutations and FLT3, IDH1 and IDH2 mutations go together; there is a correlation between genetic mutations.4.1 case of DNMT3A mutation is found among CML patients, but the genetic mutation belongs to synonymy mutation.