Objective:Toclonemultidrugresistance(MDR)relatedgenesinlungadenocarcinomacelllines.Methods:ThedifferentiallyexpressedcDNAfragmentsbetweenA549andA549DDPcellswereanalyzedbymRNAdifferentialdisplayPCR(DDRT-PCR).ThefragmentsthusobtainedwerefurtheranalyzedbyDNAsequencingandNorthernblotting.Results:ThreedifferentiallyexpressedcDNAfragmentswereobtainedandconfirmedbyNorthernblot.Sequenceanalysisrevealedthattwoofthemwerenovelandonewas100%identicalwithICEgene.Conclusion:AnalyzingdifferentiallyexpressedfragmentbetweenA549andA549DDPcellsmaybehelpfulforfindingnewMDRrelatedgenes.ThedrugresistanceofA549DDPcellsmayberelatedtotheinhibitionordown-regulationofICEgene.