The Study Of Clinical Characteristics And Prognosis Of Runx1-runx1t1 Positive Acute Myeloid Leukemia Based On Next-generation Sequencing

Aim:To investigate the combined gene mutation spectrum,clinical characteristics and prognostic factors of RUNX1-RUNX1T1 positive acute myeloid leukemia patients based on next-generation sequencing.Methods:113 AML patients with positive RUNX1-RUNX1T1 who treated in our center from January 2016 to December 2020 were retrospectively collected.The clinical data of blood routine and bone marrow smear,flow cytometry,chromosome and gene mutation analysis before treatment were collected.The patients who completed at least two courses of consolidation chemotherapy or received allogeneic hematopoietic stem cell transplantation were included in the prognostic analysis to clarify the clinical characteristics and prognostic factors of the patients.Results:The median age of 113 diagnosed RUNX1-RUNX1T1 positive AML patients was 46 years old,the sex ratio was close to 1:1,and median WBC was 7.4×10~9/L,the proportion of median primordial cells in bone marrow was 57%,101 patients had chromosome results,and 70.30%（71/101）had additional chromosome abnormalities.111 cases underwent next-generation sequencing.89.19%（99/111）of the patients had at least one gene mutation.The most common gene mutations were KIT（39.64%）,NRAS（19.81%）and FLT3（15.32%）.According to the functional classification,tyrosine kinase signaling pathway related mutations were the most common（65.77%）,followed by epigenetic regulation related mutations（25.23%）,and patients with 1～2 gene mutations were the most,was 33（29.73%）.Among these gene mutations,the most common mutation combination was KIT/NRAS（8.11%,9/111）.The proportion of KIT D816 in patients>45 years old was higher than that in patients≤45 years old（P=0.033）.The proportions of ASXL1（P=0.029）and tyrosine kinase signaling pathway（P=0.011）in patients whose WBC>25×10~9/L were higher in whose WBC≤25×109/L patients,and NRAS（P=0.024）had the same results.Among the 64 patients included in the prognosis,the higher the number of leukocytes at the initial diagnosis,the shorter the OS time（P=0.03）,and the RFS was not statistically significant（P=0.234）.Patients with KIT-D816 mutation had significantly shorter OS and RFS（P=0.007,P=0.003）,patients with FLT3 also had poorer OS and RFS（P=0.002,P=0.002）.According to the functional classification,patients with tyrosine kinase signaling pathway related gene positive have poor OS and RFS（P=0.015,P=0.021）.According to the existence or deletion of epigenetic regulation/DNA methylation（C）,laminin complex（C）and splice（S）gene mutations,two gene subgroups are defined:CCS positive and CCS negative.There was no statistical significance in OS（P=0.078）and RFS（P=0.512）between CCS positive group and CCS negative group,but the survival curve showed that CCS positive patients had a better prognosis.Among minimal residual diseases,patients who turned negative by flow cytometry after 2 courses had better OS and RFS（P=0.007,P=0.047）,while there was no significant difference in OS and RFS in patients with RUNX1-RUNX1T1 quantitative reduction of more than 3 log values after 4 courses of chemotherapy.In multivariate analysis,leukocyte count,KIT D816and flow cytometry after 2 courses were independent risk factors affecting OS,while KIT D816,FLT3 and flow cytometry after 2 courses were independent risk factors affecting RFS.In the analysis of factors affecting minimal residual disease,the positive proportion of FLT3-ITD gene mutation in patients with flow cytometry negative after two courses of treatment was significantly lower（P=0.046）.The proportion of KIT D816 mutation in patients with RUNX1-RUNX1T1 quantitative 4 courses of chemotherapy decreased by more than 3 log values was lower than that in patients without 3 log values（P=0.012）.Conclusion:1.1.RUNX1-RUNX1T1 fusion gene positive AML with additional chromosome abnormalities accounted for 70.30%,and sex chromosome deletion accounted for 53.47%.2.Up to 89.19%of patients with positive RUNX1-RUNX1T1 fusion gene AML had a median of 2（1～8）gene mutations at the time of diagnosis,and more patients combined with 1～2 gene mutations.The most common mutation was KIT mutation,followed by NRAS and FLT3.According to the functional classification,tyrosine kinase signal pathway related mutations were the most common,followed by epigenetic regulation related mutations.3.The proportion of KIT D816 mutation was high in patients aged>45 years.Patients with WBC>25×10~9/L had a high proportion of mutations in ASXL1,NRAS and tyrosine kinase signaling pathway genes.4.In univariate analysis,leukocyte count,KIT D816,FLT3,tyrosine kinase signal pathway related mutations and flow MRD after two courses of treatment were the risk factors of OS.KIT D816,FLT3 and flow MRD after two courses of treatment were the risk factors affecting RFS.5.In multivariate analysis,leukocyte count,KIT D816 and flow MRD after two courses of treatment were independent risk factors for OS.KIT D816,FLT3 and flow MRD after two courses of treatment were independent risk factors affecting RFS.6.FLT3-ITD gene mutation affects the flow pattern after treatment 2,and KIT D816 affects RUNX1-RUNX1T1 after treatment 4.