11MAY2017|VOL545|NATURE|187ARTICLEdoi:10.1038/nature22081VisualizationandtargetingofLGR5+humancoloncancerstemcellsMarikoShimokawa1*,YukiOhta1*,ShingoNishikori1,2,MamiMatano1,AiTakano1,MasayukiFujii1,ShoichiDate1,2,ShinyaSugimoto1,TakanoriKanai1&ToshiroSato1Mostcancerdeathsareattributedtotumourrecurrenceandmetastasis.ThesefeaturesmightoriginatefromasubsetofcancercellsreferredtoasCSCs1,2.TheexistenceofCSCswasfirstdemonstratedinleukaemiathroughfunctionalrepopulationassays,inwhichprospectivelyisolatedCSCsregeneratedoriginalneoplasticlesionsuponxenografting3.ThexenotransplantationassayhasbecomethegoldstandardassaytodefineCSCs.However,therearesomelimitationswithregardstotheuseofxenotransplantationforepithelialcancers,suchascolorectalcancers(CRCs)4–6.TherepopulationassayhasdemonstratedtheexistenceofCRCstemcells,butsortedCRCcellsshowpoorengraftment,evenafterenrichmentforCSCmarkers,whichiscontrarytothehighimplanta-tionefficiencyofintacttissuefragments7–10.Unlikehaematopoieticcells,sortedepithelialcellsundergoanoikisduringdetachmentfromthetissues.Furthermore,epithelialstemcellsarepassivelyregulatedbytheadjacentnicheenvironmentsandreallocationofthesortedcellsintounrelatedrecipientenvironmentscouldperturbtheoriginalstemcellhierarchy6,11.Therefore,therepopulationefficiencymayreflecttherobustnessorfitnessofthetransplantedcellsintherecipientnicheratherthanpasthistoryofstemnessinthebodyoftheoriginalpatient.Tocircumventthedrawbacksofthisassay,lineagetracingofgeneticallymarkedcells12hasbeenusedtoidentifyCSCsingeneticallytractablemousetumourmodels13–15.However,developmentofanexperimentalplatformforimplementinglineagetracinginhumancancershasbeenchallenging.VisualizingLGR5andKRT20expressioninCRCRecently,wehaveestablishedacolorectaltumourorganoidlibrary(CTOL)16thatspansdiverseclinicalstagesandsubtypes.Theextentofcellularheterogeneitywithinagivencolontumourvariesconsiderablyamongpatients.ToselecttheCRCorganoids(CCOs)thatretainstemcellhierarchy,weanalysedLGR5andKRT20expressionfromthe...
