急性单核细胞白血病M5a和M5b细胞遗传学与临床表现的比较.docx
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急性单核细胞白血病M5a和M5b细胞遗传学与临床表现的比较
急性单核细胞白血病M5a和M5b细胞遗传学与临床表现的比较
【摘要】 为了比较急性单核细胞白血病M5a和M5b细胞遗传学差异,并研究其与临床行为之间的相互关系,采用骨髓直接法和24小时短期培养法制备染色体标本,用G显带技术对58例成人初发急性单核白血病细胞进行核型分析,同时对其临床资料进行回顾性研究。
结果表明:
58例患者中正常核型28例,异常核型30例,其中正常核型在M5b中出现率高于M5a(P=0.0001),异常核型中11q23异常和+8染色体在M5a中均较M5b常见(P<0.01);临床上异常核型的M5患者常有高白细胞(WBC)计数,中枢神经系统浸润,完全缓解(CR)率低及存活期明显缩短的特征。
结论:
急性单核细胞白血病在遗传和临床上是一组异质性疾病,但M5a和M5b似乎具有各自独特的遗传学背景和临床表现。
【关键词】急性单核细胞白血病;AML-M5a;AML-M5b;细胞遗传学
ComparisonofCytogeneticsandClinicalManifestationsbetweenM5aandM5bofAcuteMonocyticLeukemia
AbstractTocomparethecytogeneticdifferencebetweenM5aandM5bofacutemonocyticleukemiaandtostudythecorrelationbetweenkaryotypesandclinicalmanifestations,atotalof58casesofdenovoadultAMLM5havebeeninvestigated.Chromosomemetaphasesofbonemarrowcellswerepreparedbyusingdirectmethodand24hoursshort-termculture.ThekaryotypeswereanalyzedbyG-banding.Meanwhile,clinicalinformationofthesecaseswerestudiedretrospectively.Theresultsshowedthattherewere28withnormalkaryotypeand30withaberrantkaryotypein58cases.ThefrequencyofnormalkaryotypeinpatientswithM5bwassignificantlyhigherthanthatinpatientswithM5a(P=0.0001).The11q23aberrationsandtrisomy8weremorecommoninpatientswithM5aincomparisonwithpatientswithM5b(P<0.01).ThepatientswithAMLM5withaberrantkaryotypehadahigherincidenceofhyperleucocytosis,extramedullarycentralnervesysteminfiltration,lowercompleteremission(CR)rateandshorteroverallsurvival.Itisconcludedthatacutemonocyticleukemiaisaseriesofheterogeneousdiseases,adistinctivecytogeneticfeaturescanbeobservedbetweenpatientswithAMLM5aandM5b,theseresultswillprovideinsightsintotheclassificationandpathogenesismechanismofAMLM5atmolecularlevel.
Keywordsacutemonocyticleukemia;AML-M5a;AML-M5b;cytogenetics
Acutemyeloidleukemia(AML)canbeclassifiedbyFABsystemintodifferentgroupsbasedoncellularmorphologyandcytochemistrystainingofbonemarrowcells.Accordingtothedifferentiationstageofmonocyticcells,acutemonocyticleukemia(AML-M5)consistsoftwogroups:
M5a,thepercentageofmonoblastsis≥80%;M5b,themajorityofmonocyticcellsarepromonocytes(blasts<80%)[1].Inaddition,hematologicalmalignanciescanbeclassifiedaslymphocytic,myeloid,histocyticandmastocyticseriesbasedontheoriginofmalignantcellsbytheWHO.Eachgroupisdeterminedbymorphology,cytogeneticsandclinicalcharacteristics.However,thesetwoclassificationsystemscannotbeusedtodifferentiatethecytogeneticcharacteristicsandclinicalmanifestationsbetweenpatientswithM5aandM5b.Inthepresentstudy,weinvestigated58newlydiagnosedAMLM5patientsinordertobettercharacterizethecytogeneticchangesandclinicalmanifestationsofthesepatientsformoreaccurateclassificationandunderstandingofthepathogene-sisofthedisease,whichcouldleadtothedevelopmentofanoveltherapeuticstrategy.
MaterialsandMethods
Patients
DuringtheperiodfromJanuary2000toJune2004,58patientswerenewlydiagnosedwithAMLM5inthedepartmentofHematologyofUnionHospitalaffiliatedtoTongjiMedicalCollege,HuazhongUniversityofScienceandTechnology(Wuhan).Theclinicalrecordsandlaboratorytestreportsofthesecaseswerereviewed.Theclinicaldiagnosiswasmadebasedontheclinicalsymptoms,peripheralbloodcounts,bonemarrowexamination.26outofthe58patientswereclassifiedasM5aand32asM5b.Therewere12malesand14femalesofAMLM5apatients,agedfrom18to59withamedianageof39.5,while20malesand12femalesofAMLM5bpatientsagedbetween28to66withamedianageof48.
Cytogeneticanalysis
2-3mlsofheparinizedbonemarrowfrompatientswereculturedinRPMI1640supplementedwith20%fetalcalfserumand20U/mlheparin.Thecelldensitywasadjustedto1×106/ml.Thesampleswereincubatedat37℃for24hours,thentreatedbycolchicineswiththefinalconcentrationof0.05μg/mlforanother42minutes.Standardcytogeneticpreparationwasmade;amodifiedchromosomebandingtechnique(G-banding)wasused.Forchromosomeanalysisatleast30-50metaphasechromosomesshouldbecountedineachsample,and10metaphasechromosomeswereanalyzedbymicroscopyormicrophotography.KaryotypeswereanalyzedaccordingtotheInternationalSystemforCytogeneticNomenclature(ISCN.1995).
Protocols
Allpatientsweretreatedwithregimensasfollows:
(1)DA(daunorubicin45mg/m2perdaybyintravenousinfusion(iv),day1to3,pluscytarabine100-200mg/m2perdaybyintramuscularinjection(im)day1to7);
(2)HA(homoharringtonine2-3mg/m2byivperday,day1to3,pluscytarabine100-200mg/m2perdaybyim,day1to7);(3)IA(idarubicin10mg/m2perdaybyiv,day1to3,pluscytarabine100-200mg/m2perdaybyimday1to7);(4)MEA(mitoxantrone8-12mg/m2perday,day1to3,plusetoposide100mg/m2perdaybyivdrip,day4to5,pluscytarabine100-200mg/m2perdaybyim,day1to5).Subsequently,somepatientsreceivedstrengtheningchemotherapywithcytarabine1.5g/m2twiceadayfor6days,whilepatientsolderthan70yearsreceivedthesametherapyforonly3days.Outofthe58patients,twounderwenthumanleukocyteantigen-matchedallogeneicbonemarrowtransplantationandoneunderwentperipheralbloodstemcelltransplantationafterthediseaseswentintocompleteremission.
Definitionofresponse
Completeremissionwasdefinedineachprotocolasabsenceofleukemiainthebonemarrowindicatedbylessthan5%blasts,recoveryofnormalperipheralbloodcellcountsasindicatedbyabsoluteneutrophilcount≥1.5×109/L,andplateletcount≥100×109/L,andabsenceofextramedullaryleukemia.
Statisticalanalysis
ClinicalandcytogeneticcharacteristicsofAMLM5apatientswerecomparedwiththatofAMLM5bpatientsusingχ2test.
Results
Cytogeneticanalysis
Outof58patients,28(48.3%)hadnormalkaryotypes,thefrequencyofwhichwassignificantlyhigherinthepatientswithAMLM5b(85.7%,n=24)thanthatinthepatientswithAMLM5a(14.3%,n=4)(P<0.01);30(51.7%)hadaberrantkaryotypesbeinginvolvedin11q23/MLL(AMLM5avsAMLM5b:
833%vs16.7%,P<0.01),soletrisomy8(AMLM5avsAMLM5b:
88.9%vs11.1%,P<0.01),trisomy8plus11q23/MLL(AMLM5avsAMLM5b:
333%vs66.7%)andotherchromosomeabnormalities,outofwhichtrisomy21intwopatients,5q-inone,7q-inone,t(9;22)inone,andt(8;16)inanotherone.TheresultsofcytogeneticanalysisforallAMLM5patientsaresummarizedinTable1. Clinicalcharacteristics
Outofallthepatients,abnormallyhighwhitebloodcellcounts(≥50×109/L)weredetectedin27patients(M5avsM5b∶14vs13);hepatosplenomegalywasobservedin22patients(M5avsM5b∶11vs11);extramedullarydiseaseintheskinwasfoundin16patients(M5avsM5b∶9vs7),enlargementoflymphnodesin20patients.15patientshadcentralnervoussystemleukemia(M5avsM5b∶9vs6);14patientshadthedisseminatedintravascularcoagulation(M5avsM5b∶8vs6).
Thecompleteremissionratewas42.3%(n=11)forpatientswithM5a,56.3%(n=18)forpatientswithM5b,and50%(n=29)forallAMLM5patients.Thepercentageoftheone-yeardisease-freesurvival(DFS)inpatientswithAMLM5awas26.9%(n=7),whileitwas34.4%(n=11)inpatientswithAMLM5b.Theclinicalcharacteristicsbetweenthetwosubtypeswerenotsignificantlydifferent(P>0.05).TheseresultsarelistedinTable2.Table1.CytogeneticdataforpatientswithAMLM5subtypes(略)Table2.ClinicalcharacteristicsofAMLM5patientswithvariouskaryotypes(略)
Discussion
Specificnon-randomchromosomalabnormalitiesareoftenobservedincertainsubtypesofhematologicmalignancy.MoreaberrantcytogeneticshasbeendiscoveredinpatientswithAMLM5afterinitiallyfindingoft(9;11)(p21;q23)inM5apatientbyBerger[2]in1980.Haferlachetal[3]consideredthat11q23aberrationandtrisomy8weresignificantlyassociatedwithAML-M5.Tkachuketal[4]foundthat11q23abnormalitiesareinvolvedintheMLLgene(ornamed“ALL1”or“HRX”),spanning90kbofcDNAandencodinga3968-aminoacidproteinwithmolecularmassabout430kD.Thewild-typeMLLproteinhasthreeAT-hookDNAbindingdomainsandmultiplezincfingerdomains.MLLgene-encodedproductasatranscriptionfactorthenmaybindwiththegenesregulatingbodydevelopmentandcelldifferentiation[5].ThegenerearrangementsofMLLsuchas11q23translocationalteritsstructureandfunctionandmayleadtoleukemogenesis.
Meanwhile,thetrisomy8isachromosomeabnormality.Althoughtheinducingmechanismandthebiologicroleofthetrisomy8areunknown,therelationshipbetweenthetrisomy8andmonocyticmalignancyhasbeensuggested[6].Theoccurrenceoftrisomy8mayenhancetheexpressionofgenes,leadingtothedevelopmentofleukemias.Inthisstudy,theincidenceof“normalkaryotypes”washigherinpatientswithM5bthanthatinpatientswithM5a(P<0.001);theinvolvementof11q23aberrantionsandtrisomy8weredetectedmorefrequentlyinpatientswithM5athanthatwithM5b(P<0.01)inaccordancewithpriorstudies[3,6].TheseresultsindicatethatthegenomicinstabilityismorecommonandcomplexinM5apatientleukemiccellsthanthatinM5bcells.
TheclinicalcharacteristicsofpatientswithAMLM5includedextramedullaryinfiltrationwithhighWBCcounts,lowcompleteremissionrateandshortdisease-freesurvival(DFS).Inourstudy,nosignificantdifferencewasfoundregardingthosecharacteristicsbetweenthetwosubtypes,inagreementwiththeresultsfromthestudyoftheEasternCooperativeOncologyGroup(ECOG)on81patientswithAMLM5[1].
Meantime,Schochetal[7]analyzed1897AMLcaseswith11q23abnormalities,an