Clinical Significance Of DNMT3A Gene Mutation In Acute Myeloid Leukemia

ObjectiveBy detecting the DNA methyltransferase 3A(DNMT3A)gene,the mutation rate,mutation site,and clinical characteristics of the patients with adult acute myeloid leukemia(AML)were analyzed.Comparing the overall survival(OS)and relapse-free survival(RFS)of DNMT3A mutant and wild-type to determine the effect of DNMT3A gene mutation on the prognosis of AML.The WT1 gene expression levels in newly diagnosed AML patients were measured by RT-PCR to compare the difference in WT1expression levels between the DNMT3A mutant and wild-type.WT1,an independent prognostic factor,was used to reflect the prognosis of the DNMT3A mutation group.This will provide guidance for the gradual improvement of the classification system for prognosis judgment and targeted therapy in furture.Methods1.Extracting bone marrow specimens or peripheral blood(the proportion of primordial cells exceeds 20%)of patients with AML 3-5mL,EDTA anticoagulant treatment,using flow cytometry and genetic to type AML and extract genomic DNA.DNMT3A Gene 23rd exon was amplified by using PCR and the products were purified to be directly sequenced.2.The expression level of WT1 gene was detected by Taqman probe fluores cence quantitative PCR method.ABL was used as the reference gene,and the relative expression was calculated by WT1 copy number/ABL copy number.ResultsAmong the 132 newly diagnosed adult AML patients,72 were males with a median age of 51.5 years(18-80 years)and 60 women.The median age was 52 years(21-80 years),of which M0 type 5 cases and M1 type 6 For example,M2 type 48cases,M3 type 28 cases,M4 type 22 cases,M5 type 18 cases,M6 type 3 cases,M7type 2 cases,a total of 14 cases of DNMT3A mutations were detected,the mutation ratio was about 10.6%,in which M2 Type 6 cases(12.5%),M4 type 4 cases(18.2%),and M5 type 4 cases(22.2%).In all mutation types,5 cases were R882H,all were M2type;4 cases were R882C,which were M2 type 1 and M4 type 3 cases;5 cases were R882P,which were M4 type 1 and M5 type 4 cases respectively.Other types such as R882S are not detected.In all cases,there were 58 cases of normal karyotype chromosomes,accounting for 43.6%.Of these 58 cases,11 cases had DNMT3A gene mutation,accounting for 19.0%.The number of DNMT3A mutations in 74 patients with chromosomal abnormalities was only 3,with a ratio of only 4.1%.Three patients in the DNMT3A mutation group had a chromosomal abnormality,and the remaining11 patients all had karyotyped normal chromosomes,accounting for 78.6%of the patients.The DNMT3A wild-type patient was 58.0±18.8 years old,and the median white blood cell count was 37.9(0.75-332.13)×10~9/L,hemoglobin 65(22-110)g/L,and platelet 27(4-208)×10~9/L.Peripheral blood progenitors were 45.5%(0.0-93.0%),bone marrow blasts were 74.8%(20.0%-95.0%);DNMT3A mutations were 52.9±16.7years old,and median white blood cells were 13.3(0.54-322.0)×10~9/L,Hemoglobin66(36-110)g/L,Platelets 43(15-103)×10~9/L,Peripheral blood progenitors 76.5%(0.0-97.0%),Bone marrow blasts 75.3%(20.0%-95.0%)),There was no statistically significant difference between the two groups of data,P values were greater than 0.05.The median relative expression of WT1 was 3.77(0.008-110.5)in the mutant group and 1.89(0.005-76.1)in the wild group,and the P value was<0.05.There was a significant difference,that is,the relative expression level of WT1 was higher in the DNMT3A mutation group than in the mutant group.Wild group.Three-year OS in the mutation group(21.4%vs 65.3%)and RFS(14.3%vs 58.5%)were shorter than those in the wild group and there was a statistical difference(P<0.05).Conclusion1.In this study,the proportion of DNMT3A gene mutations in newly diagnosed adult AML patients was approximately 10.6%,and the hotspot mutation site was R882.2.There was no statistically significant difference in the proportion of age,peripheral white blood cells,hemoglobin,platelets,peripheral blast cells,and bone marrow blast cells in DNMT3A-mutant AML patients.3,DNMT3A gene mutations occur in patients with CN-AML,the proportion is about 19.0%.In the DNMT3A mutation group,the majority of patients were normal karyotypes,accounting for 78.6%of the patients.4.The relative expression of WT1 in the DNMT3A mutant group was higher than that in the wild group.There was a statistically significant difference between the DNMT3A mutant group and the wild group.This indicates that the DNMT3A mutation group has a worse prognosis than the wild group.There may be a regulatory correlation between the two at the molecular level,which may affect the occurrence of AML synergistically.5.The OS and RFS of patients with DNMT3A mutation group were significantly shorter than those of wild group,suggesting that the mutation group had a poor prognosis.