Analysis Of Gene Mutations In 152 Cases Of MPN Patients And Clinical Characteristics Of PMF With ASXL1 Gene Mutation

PurposeTo analyze the genetic mutations and clinical characteristics of patients with myeloproliferative neoplasm(MPN),to analyze the incidence and clinical features of mutant genes in patients with MPN.And to explore the incidence of ASXL1 gene and co-mutated genes in primary myelofibrosis(PMF)patients and their relationship with clinical characteristics.MethodsThe clinical data of 152 patients with MPN treated in the First Affiliated Hospital of Zhengzhou University from January 2017 to January 2021 were collected retrospectively and followed up.There were 73 males and 79 females,with a median age of 57(17-84)years old.These patients were referred for polycythemia vera(PV,n=41),essential thrombocythemia(ET,n=75)and PMF(n=36).The next-generation sequencing method was used to detect 38 gene mutations,and SPSS 26.0 software was used for statistical analysis.Result1.Clinical characteristics:Among the three subtypes of MPN,PMF patients are older than PV and ET patients but not significant.Compared with PV and ET patients,PMF patients have more severe myelofibrosis(P<0.001),lower HGB(P<0.001)and PLT level(P<0.001);Patients with ET have higher PLT(P<0.001),and patients with PV have higher HGB(P<0.001).The incidence of splenomegaly in PMF patients was significantly higher than ET and PV patients.The incidence of thrombotic events in PMF patients was lower than ET and PV patients,and there was no significant difference in the incidence of thrombosis in ET and PV patients.2.Gene mutations detection status:①Total of 221 mutations in 23 genes were detected in 132 patients(86,8%),1(70/152)or 2(46/152)mutations were detected in 116 cases(76.3%),and 9 cases(5.9%)were detected 3 mutations(2 ET,1 PV,6 PMF),4 mutations(1 ET,3 PMF)were detected in 4 cases(2.6%),and 3 cases(2.0%)were detected>5 mutations,per capita carried(1.45±1.02)mutations.There was significant positive correlation between age and number of mutations in all MPN patients(rs=0.306,P<0.001).16 cases(10.5%)detected>3 mutation genes,and the degree of myelofibrosis was significantly higher than patients with<3 mutation genes(z3.356,P<0.001),and HGB was significantly reduced(z=-4.268,P<0.001).②The 221 mutations of 38 genes were classified according to the function of the gene,in descending order of mutation frequency,the highest frequency was activation signaling pathway genes(52.5%,116/221),DNA methylation genes(14.9%,33/221),chromatin-modified genes(13.6%,30/221),spliceosome and RNA metabolism genes(5.4%,12/221),tumor suppressor genes(2.3%,5/221)and histone methylation genes 0.5%(1/221)etc.③HMR mutations were detected in 30 cases(19.7%).HMR mutations are more common in male patients.Compared with patients without HMR mutations,they have lower HGB level(z=-4.226,P<0.001)and higher degree of myelofibrosis(z=-3.356,P=0.001).The incidence of splenomegaly is higher than patients without HMR mutations(x2=9.251,P=0.004).④Among the driver genes,JAK2 is the most common gene mutation,followed by CARL,and MPL has the lowest mutation rate.⑤The incidence of non-driver genes and the number of mutant genes in PMF are higher than ET and PV.Among them,ASXL1 had the highest mutation rate in PMF patients(50.0%,18/36),and the incidence was significantly higher than PV and ET patients(P<0.001).There was no significant difference between PV and ET patients(P=0.718).In addition,U2AF1 and NRAS in PMF were significantly higher than ET and PV patients(P<0.001).3.Clinical features and gene mutations in triple-negative MPN:A total of 28 triple-negative MPN cases were detected,accounting for 18.42%,7 cases were PMF(19.4%),3 cases were PV(7.3%),and 18 cases were ET(24.0%).Compared with classic MPN,patients with triple-negative MPN are younger,have lower HGB levels and WBC counts.4.Clinical characteristics of patients with ASXL1 mutation-positive PMF:①A total of 18 ASXL1 mutation-positive PMF patients(50%)were detected in this study.Compared with ASXL1 mutation-negative PMF,ASXL1 mutation-positive patients had higher MPN 10 score(t=-3.572,P=0.002),and there are more patients in the middle-risk-2/high-risk group(Z=-2.057,P=0.041)according to the DIPSS-plus score.The leukemia conversion rate was higher than ASXL1 mutation negative group,but the difference was not statistically significant..②Of the 18 PMF patients with positive ASXL1 mutations,16 of them(88.9%)detected a driver gene mutation,12 patients(66.7%)had at least one other non-driver gene.The common co-mutation genes were JAK2(61.1%,11 cases),NRAS(33.3%,6 cases),CARL(22.2%,4 cases)and U2AF1(16.7%,3 cases).CEBPA,TP53,and IDH2 were not detected.Conclusion1.Different types of MPN have different mutation gene frequencies,distributions,clinical characteristics and laboratory indicators.2.Compared with classic MPN,patients with triple-negative MPN are younger,have lower HGB levels and WBC counts.There was no difference in non-driver gene mutation rate and the number of mutant genes between the two groups.3.Nearly half of MPN patients have at least one non-driver gene mutation.There was significant positive correlation between age and number of mutations in all MPN patients.4.Among the three subtypes of MPN,the mutation rate and number of non-driver genes in PMF were higher than ET and PV;The mutation rate of ASXL1,U2AF1,and NRAS in PMF is significantly higher than ET and PV patients.ASXL1 gene often co-mutated with other genes in PMF patients.5.ASXL1 mutation-positive PMF patients may be associated with higher symptom burden and poor prognosis,but further studies are needed to confirm.