Analysis Of The Clinical Features And Prognosis Of PML-RARα Fusion Gene Subtypes In Acute Promyelocytic Leukemia

Background and purposeThe specific PML-RARα fusion gene of acute promyelocytic leukemia(APL)distinguishes it from other acute myeloid leukemia(AML)and has a good prognosis.However,APL is still associated with a high risk of early death and recurrence.At present,there is lack of consummate risk assessment system about APL.Targeting PML-RARα fusion gene is the key to the realization of differentiation therapy.For the study of PML-RARα fusion gene,it is found that there are three classical L,V,S subtypes.This paper will explore the possible clinical and prognostic characteristics of APL from three PML-RARα fusion gene subtypes,and provide a reference for making more complete APL diagnosis and treatment scheme and risk assessment.MethodsTwo hundred and one APL patients,who were newly diagnosed in Hematology Department of the First Affiliated Hospital of Harbin Medical University from January 2015 to January 2020,were putted into different groups according to PML-RARα fusion gene subtypes L,S,V.Clinical data of patients in each group were analyzed and compared,including patients’ basic information,the results of the laboratory examination at first diagnosis,as well as the patients’ treatment methods,results,and prognosis.Peripheral blood laboratory examination includes blood routine,coagulation item,lactate dehydrogenase,bone marrow laboratory examination includes chromosome karyotype,immunophenotype,gene mutation.IBM SPSS Statistics 23.0 statistical software was used for statistical analysis.Results(1)In APL patients,the proportion of PML-RARα fusion gene L,S,V subtypes was 57.21%,38.31% and 4.48%,respectively.The mean age of L,S,V subtypes was41.27 ± 17.03 years,43.19 ± 15.48 years and 50.22 ± 17.44 years,respectively.All subtypes were more common in middle-aged people.There was no significant difference in age and gender among the three subtypes(P > 0.05).(2)In the laboratory test of peripheral blood,there were significant differences in WBC count,PT and LDH levels among the three subtypes(P < 0.05).S subtype had higher WBC count,LDH level and longer PT than L subtype(P < 0.05).However,the results of peripheral blood laboratory tests which between S subtype and V subtype,L subtype and V subtype showed no difference(P >0.05).The risk stratification of APL was based on WBC count at first diagnosis,there were differences among the three subtypes(P < 0.05).S subtype had a higher proportion of high-risk patients than L subtype(P<0.05).However,the risk stratification which between S subtype and V subtype,L subtype and V subtype showed no difference(P > 0.05).(3)In the laboratory test of bone marrow,there were significant differences in CD56 expression and FLT3-ITD mutation among the three subtypes(P < 0.05).S subtype had higher CD56 positive rate and FLT3-ITD mutation rate than L subtype(P < 0.05).However,the results of bone marrow laboratory tests which between S subtype and V subtype,L subtype and V subtype showed no difference(P > 0.05).(4)The incidence rate of DIC was statistically different among the three subtypes(P < 0.05).Pair comparison after ANOVA showed that the incidence rate of DIC in S subtype was higher than in L subtype and V subtype(P < 0.05).However,the incidence rate of DIC which between L subtype and V subtype showed no difference(P > 0.05).(5)Follow-up of patients showed that the mean OS time and RFS time were statistically different among the three subtypes(P < 0.05).S subtype had shorter OS time and RFS time than L subtype(P < 0.05).However,the mean OS time and RFS time which between S subtype and V subtype,L subtype and V subtype showed no difference(P > 0.05).The survival analysis of OS rate and RFS rate which among the three subtypes showed no difference(P > 0.05).Conclusions(1)In APL patients,the proportion of PML-RARα fusion gene L,S,V subtypes is 57.21%,38.31% and 4.48%,respectively.(2)In APL patients,S subtype of PML-RARα fusion gene is more likely to appear in high-risk patients.(3)S subtype of PML-RARα fusion gene is frequently with some possible high risk factors including elevated LDH level,CD56 positive rate and FLT3-ITD mutation rate.(4)In APL patients,S subtype of PML-RARα fusion gene is more prone to DIC than L and V subtypes.However,the incidence rate of DS among the three subtypes shows no difference.(4)The mean OS time and RFS time of S subtype are shorter than those of L subtype.(5)The PML-RARα fusion genotyping of APL has the potential to be used as an assessment tool for APL prognosis,which needs further research and exploration.