REVIEWOpenAccessTheroleofcancer-derivedmicroRNAsincancerimmuneescapeMingYi1,LinpingXu2,YingJiao1,SuxiaLuo2,AnpingLi2andKongmingWu1,2*AbstractDuringmalignanttransformation,accumulatedsomaticmutationsendowcancercellswithincreasedinvasivenessandimmunogenicity.Underselectivepressure,thesehighlyimmunogeniccancercellsdevelopmultiplestrategiestoevadeimmuneattack.Ithasbeenwellestablishedthatcancercellscoulddownregulatetheexpressionofmajorhistocompatibilitycomplex,acquirealterationsininterferonpathway,andupregulatetheactivitiesofimmunecheckpointpathways.Besides,cancercellssecretnumerouscytokines,exosomes,andmicrovesiclestoregulatethefunctionsandabundancesofcomponentsinthetumormicroenvironmentincludingimmuneeffectorcellsandprofessionalantigenpresentationcells.Asthevitaldeterminantofpost-transcriptionalregulation,microRNAs(miRNAs)notonlyparticipateincancerinitiationandprogressionbutalsoregulateanti-cancerimmuneresponse.Forinstance,somemiRNAsaffectcancerimmunesurveillanceandimmuneescapebyinterferingtheexpressionofimmuneattack-associatedmolecules.Agrowingbodyofevidenceindicatedthatcancer-derivedimmunemodulatorymiRNAsmightbepromisingtargetstocounteractcancerimmuneescape.Inthisreview,wesummarizedtheroleofsomemiRNAsincancerimmuneescapeanddiscussedtheirpotentialclinicalapplicationastreatmenttargets.Keywords:microRNA,Cancerimmunesurveillance,Immuneescape,Immunotherapy,Tumormicroenvironment,ExosomeBackgroundRobustanti-cancerimmuneresponseconsistsofaseriesofstepwiseimmuneeventsincludingthereleaseofcancer-associatedantigens,theprocessingandpresenta-tionofantigenpresentationcells(APCs),theprimingandactivationofnaïveTcells,thetraffickingandmigrationofactivatedTcells,andthetumor-killingactivityofeffectorcells[1,2].Actually,theanti-cancerimmuneresponseisahighlycomplexprocesswhichcouldbestrengthenedorweakenedbymultiplefactorssuchasimmuneediting,transforminggrowthfactor-β(TGF-β)signaling,andim-munecheckpoints[3–5].Thebalancebetweenimmuno-stimulatoryand-inhibitoryfactorsiscrucialtomaint...
