| Myelodysplastic syndromes(MDS)are a common group of hematological malignancies with high risk of progression to leukemia.Due to the high tumor heterogeneity,existing IPSS-R staging combined with clinical features and cytogenetic abnormalities cannot accurately predict disease progression.Although there have been studies on the molecular characteristics of MDS and some progress have been made,there are limited studies on the changes of genomes at various stages of progress,the interactions between gene mutations and their upstream and downstream relationships,and the results of each study are not the same.Therefore,this experiment mainly analyzes the number,characteristics,driving mutations and their relationship of the gene mutation spectrum of leukemia and primary leukemia derived from MDS from low-and high-risk MDS.METHODS:This study collected 37 patients with myeloid tumors from January 2016 to December 2017 in Guangdong Province,including 10 patients with low-risk MDS and 14 patients with high-risk MDS.There were 3 cases in the AML group and 10 cases in the de novo AML(M2)group.DNA was extracted and targeted sequencing of 114 hematological tumor-associated genes was performed.After filtering and annotating the data,the bioinformatics method was used to analyze the mutation spectrum of each group of samples.MutsigCV software and oncodriveCLUST algorithm were used to find the driving mutations,and cluster analysis and path enrichment analysis were performed.In addition,statistical methods such as Fisher's test,T test,and Lasso regression were also used for gene mutation pattern analysis and comparison between groups.RESULTS:1.By performing targeted sequencing on each group of samples and filtering according to the quality value and sequencing depth,it was found that the average number of non-synonymous exons in each group was 80(73-106).Among them,the proportion of missense mutations is the highest,and the most common type of SNV is C-T.From low-risk MDS,high-risk MDS,primary AML to MDS-transformed AML,the average number of mutations in each group was 56.8,61.5,63.5,and 77,respectively.The absolute values of frame-shift deletion mutations were 16.1,21.07,20.8,and 29.97,respectively.The absolute values of missense mutations were 30.3,29.5,30.7 and 32.33,respectively,and the ratios were 53.35%,47.96%,48.34%and 35.11%,respectively.2.The genes with the highest mutation frequency in each group were:low risk group:ASXL1,ATM,FAT1,PAX5,SETBP1;high risk group:ASXLl,ATM FAT1,IL7R,JAK1;sAML group:ASXL1,ATM BRAF,CCND3,CEBPA;AML group:ASXLl,ATM DIS3,FAT1,FLT3.3.Through the comparison between groups,the genes with increasing mutation frequency from low-risk MDS,high-risk MDS to sAML include BRAF IDH1,U2AF1,ZRSR2,etc.The genes with continuous decreasing trend include EZH2 and SETBP1.4.Gene ontology(GO)and Kyoto Encyclopedia of Genes and Genomes(KEGG)pathway analysis showed that the patients in each group were in myeloid cell differentiation,cell regulation,and hematopoiesis.Regulatory,transcription factors and other pathways were enriched,and there was no significant difference in pathway enrichment between groups.However,the frequency of mutations in most splice pathway genes increased with disease progression,while the RAS pathway-related genes were more frequently mutated in the AML and sAML groups.CONCLUSIONS:1.From low-risk MDS,high-risk MDS,primary AML to MDS-transformed AML,the total number of mutations is increasing,and the absolute value and proportion of frame-shifting mutations are gradually increasing.2.Gene mutations such as splice-related pathways and epigenetic-related pathways in MDS and AML groups were more common in myeloid tumors;the mutation frequency of RAS pathway genes was higher in AML group.3.The gene mutation profiles of each stage of MDS progression have their specificity,and the analysis of molecular characteristics of MDS contributes to the prediction of disease progression.4.Compared with secondary AML,primary AML contains more virus-related pathway enrichment. |
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