Часть 2 (1121000), страница 68
Текст из файла (страница 68)
r ] ( a r . : 1 t r : : 1. j . . . i ]\.-',1'ij,,d7.-'-N]DVlNNlNrctrstH9Nt))V'rNntclNUVDVNOrno t-LV'ldCNVXIIAZffipeJlxa Ja^rlpazrue6ou.roqelleuoutlesluepuaoep- a ur p r l s r q+ oa J n l l n lfl: . : 1 : : i:: : : . j : - .: j r \' ::;':.;:.;:,:,:;5./Fj:ua6elnuIerlualoo'punooLUo)lsell{!-lr.jj-''QZ-OZ a.rntld) a{orus oJJEqo} pue JE}IPoJ uI }uesald IEJIIUaqJSutsnec-raluece'auarltd[n]ozuaq pue tg utxotDl[D urxot IEBunJaql epnlf,ul{em slql uI pe]B^IlcesuaSourcJeJJo seldurexg 'clua8elnru {UBU aJE ]eql slsnpoJd saleJaua8 slPJ-rrueqJ urEual uo dlr^rtsu Jreqt '.{laleunuoJun 'spunoduoc palerJxe,,(psuapuessalruJPqolur sulxo] pelsaSur ua^uos o] dlaq ^llPtuJou selu.{zua aselq.J-'sas?plxoTgr-d aLuotqJoltJ aqt sE u^tou)I seudzua rPlnllesErlul Jo las e fq pazdptec tan11aql ur sesseoordcrloqelaru ,{q urro; eAI]JpaJaJotu P ol pe8ueqc uaeq eneq.{aqlrage i{po Sur8euep aruoJaq .{aqt l.{lecruraqJ UeuI z(1a,lpe1arare seuo }ualoderolu aq] ^,i.1praua8tnq 'VNCI uo ,tpcarrp lf,e suaSoulcrP3 eseql Jo ^ aJ V'sua8elntu aJe suaSoulcJBf,Lueur teq] spurJ euo 'pazf1euu aJeseoJnossnoIJeAruo4 E]ep &lJlue8e]nru uaq \'sllec uerpluruEru uo pelsal ueqm suolleJJeqeeuosoluoJqJ Jo suolleln{u esnBcoslp prJelsBqur desse]uarua^uoJ pue prder sql .{q JrueSElnu se peJossspunod-tuof, aql Jo rsontr'(Iz-02 am8Ic) pernseeu uaql sl slrelJBq eql Jo aler uollPlnruSuppsar aq] ierJalceq1sa}pau8rsap,(lerceds;o eJnllnJ E ol peppe sI pue (^aolaqpassnJsrp-lErurue ]3Plur ue ur sJnJJo lEql SulssaJord pcturaqf,olq eq] slrulruo]) sllec Jalrl leJ ruoq paledaJd lcpJxe Surle,ttlce uE qllllr pe4tu sI ueSouIJJp:)aq] ,ilrJrue8elnu roJ lsal uoruluoJ auo uI 'suollelnru esneo.{aq}-/ilJadoJd uour-ruo3 euo ]seal ]E aneq daq] 'seJnlf,nrlsasJaAIpeAPqsueSoulJrEl Ieclluaqc asaqlq8noqllV 'se8 pJelsnu sE qJns slue8e 3u4e1,r{1p pue 'saultuesoJ}Iu 'saulruesrleurorB se qJns uraql Jo sa^rle^IJap puP suoqJeJorpdq clleluoJe Jo aSueJe epnlcur saldurexg 'uDISJraql uo dlpaleadeJ paluled Jo slerulue ptuarulJedxaol peJ are ,(aql uaq^ cruaSourJJEJ aJe slEtllueqc aleredstp almb due141.{.ecape^l}JeoIpEJ rxoq selJlupd n pues,(erl" se qcns 'uorlerper Surzruor sB IIal sE 'aulqsuns ruo4 rq8g AII-uoIleIpEJJo sruJoJsnorrel pue sprrueqo apnlJul sua8elnru Sursnec-racueJeseql'suoq-Btnur eleraua8 os pue ygq a8eruep]eql asoq] are puetsrapun ol lselsee eql lnq'perJB^ pue,r(ueru are 'suaSoupJuJ se rr/v\oDl tarueJ esnPJ ueJ lBq] slueSe aql'llvVNCa6euec sluoov6u!sne1-re)ue) loN lng'fue6;'esuasp aqtJo.{3o1orqJelnJelorueql pauruexa a^eq e^ JeUE'uollJes }sEIaq} q JecupcJo}ueu-lpeJl aql ssnosrp ilr\a aA 'JeJuEJueunq luanard ol sr(ert Surpur; uI 'saIllncIJJIppue 'sqdurnrJ] aql Jo aruos JeprsuoJ ueql llrlr a A'JaJueJ esneo o] TI.'t,roDIare leq]stua8e leure]xe eqt ]noqe paurpal ueeq seq tEqM ]e Iool ]srIJ IIIM a i\'1ce daq],vroqqsnqelse o] Jo srolJeJ{srJ letuauuoJrlua crycads eq} dJlluapl ol-ocJeqo}'paplole aq uago;o uorldacxa aq] qlu^-sasec lsoru ur llnJrJJIp ueaq seq ]luec Jacuer leql alef,rpursuoqepdod ueunq uo suollelJesqo qons q8noqrlV'BJrrJVur suorlelndod]uangJe fyalrqeyarureual ur ,rrrolosle sI eJueprJurJaJueJ 'prauaB ur suplrJaurv Suoruu eoueprJuraq] JIeq lnoqe fpo sr 'xas Iensecpue 'sBnrp 'sellareBrc'eeJJoJ'lor{oJle pro^E oqm'(A1ureJ erues eqlJo sreqtueruSurcrlce.rd-uou Suorue 1ou ,(puelrodun '1nq) qeln q suoruJolN ]crrls SuorueresueJ Jo acuaprJur aq] ]ng 'raf,ueJJo alp ily!\ aldoad aArJur auo flalerurxorddeul)NV) lo srsnv)ilgvr.Nl^ludlHi9ZZLVNO(s)eutofl esoalso: h l f l t G V U.eulotleqlosaur:SOI-S38SV.r a ) u e ) l a p p e l q ' s e u l o u t ) l e )u t l s:)tNlsuv .seru.ra)nal n)e:lNlZNlS .e u r o l r e s o r 6 utea n r ;:lctuo'lH)]ANtA .se8upqr uepplq aq] 'a8pruep JrleuaB roJ toadxa tq8lu euo sV .pernpord seqJolerlrur aql ]Bql IIat luelnu e ruo4 pepueJsep sllasJo euols elSursp Jo slsrsuosBurollrded qrea leqt ]q8noql sl tl :pe3npur sEruollrdedJo raqrunu aq] raBrEIeqltolerlrurgo esop JorJdeql JalBeJBeql'sDruonldud pellal sJorun]eIIIue a ,u8ruaq'llplusdupluJo ]uaudole^ap aql ur sllnsal uorleJaJlloJd srqt totenrur ue olpasodxeuaaq,{lsnor^aldsEquDIsuor8erE uI '(pee}sulSuIpI^Ip enunuoJ o}}Eq}JoSuppttp dols pue alerluaJaJJrpdleurrouppo-rv\leq] slleJ esneJ ol Jo) uorswp ilaceleFrurls 01sllas uo.,(pJalrpurpup.{.I}f,aJrpqtoq }Jp esaqJ'lueuuoJr^ua leJol eqlur sasEaloJdpue srotf,EJrl}lv\oJ8qloq Jo uorlaJJeseql Sursneo,asuodseJ^,fuo1eur-tuegut ue aJnpur ol ,{FueJeddesr Je}oruoJdJourn} eJoelerpeuuraql}JaJJe'SZ-OZ aJnBIC)Jolerlrur trua8elntu qluaelueu-]EeJtE JaUEparldde ale .{aq} ^luo dcuanbar; q8rq 1BsJatupJ esnel seouelsqnsJreseqJ'(9I reldeql ur passncsrp;demqled Suqeu8rsrelnllef,ertur lolrsourldprleqd-soqd eqlJo Ued ale^rlJe ecuaq puB (JXA asourLulalotdJ1o srolB^rlJpIETJTJTUBsE a^Eqaq qJIqM '(VdJ) alplece yoqroqdldoupJepellal sp qJns ,aa1sapqtoqd.Jolerlrulare sJalouroJdJorunlpapnlsdlaprlltaqJJorunlpasodxalsoueo1'Jrua8e}nrudlsnonard uDIs ur ,{1anr1ra1asJef,ueoesneoueJsellasuaqrrouareslpJrruaqc'sraloruord JorunlleqlseuAouTseJuplsqnsolsqluoruporradJoB JeAoaJnsodxapaleadar flanrleurally.rarlree pauorlueu a.,r,rse ,1ca33aSuqoru-ord-racuer eql ur ued e ,(e1ds11acdroleuruegur leql tq8noql sr tr pue ,punome ol pe]f,eJllB eJe slleJ poolq alrq ^ ,rtroleruruegul .punoM eql Jo aSpa aql ]esllao eqtJo aruos tuo4 dolanap ol sraJupJ asnef,(uorJEJaJrIoJd1ac Surlelnruqs dq'uEJ Jolerlrur ue qJns ol eJuo pesodxauaeq seq leq] uDISSurpuno,u.dldurrg'Joluplul Jorunl.s}lnsur ,}ueeseslce,{e,rnslqturJacue3speesaqls^osuaSourJJe3}eq}JoV-JaJJIpalrnb taqlourpualo]JouaSoursJeJqll^\eqlslualuleaJlJaqunJ o1Jaqlrepasodxa aJE slleJ aql uaqm ref,uecpesealourecuaprJurdpear8 e ro; a8elsJoaql les leql suot1elnru-a8eruep cpaue8esneJseoptualel1l ,1a1rtlqerurouqe3u4se1snorlqo raqlo .{ue Jo Jorun} p ol asrJalr8 y1as1rdqsaop tanaa,roq,sua8lou-etnru esaql uoqeclldde apurs y' (vsNC) aueserqlueJolelzuaq{qleurrp punod-ruoJ paleleJ aql ro auari{d[e]ozuaq se qcns uaSourcrecSurSeuep-y5c e qrl^1,UDISaqt 3u[urcd,{1pa1eadar,r(qaJrru ur palrolla aq ueJ sJacueJuDlS'uorssar8oJdrournlJo saSelseql a^rasqo o1^,(seasr lr areq \ 'uDIsesnoru uo slEtrrueqcSursnec-JaJuel slcaJJeaq] uo o3e 3uo1euop serpnls uro4 saruoJ eJuapr^eJolsaJeelcaql'sua8elnru are recueoJo aruosJo luarudola,rap aq] JoAEJleql saluelsqns [e ]oNloN oclsJelouordtounl lylg6aoeureosroletllulJournl*rorj uoIss|,Jrradqr!M'z00z., o, I l1lfr:HJ l'rt"iil;", ",,,,"'jiJlauag :luauuol^ul aql pue lafue) uolJ elep,g)]a)ue)luauruoJtAUfasnetsuabouole)luaraJJt6tualaJJtp(B).aua6tossalddnstounl1osed,(1Egdaqt yo suottelnullsualfeleq) qllm pele!)ossesrpue s>rdol1aq1u1ro)uel ra^rlJoasne:Itolnquluo) e aq ot lq6noqt st ll suotltpuo);etrdorlprunq rapun parolsalp r(eq}uaqmslnueadpue urer6uo snnolo}eq1(aozltosnaollsnllt1tadsy)ploLup utolJutxo] e,lB ulxolDllDst ataq patellsnlllpunodurotaLll'VNOqllrvr6urlrearIq suollelnu asnp)lltMIeql aloleqsua6ouole:lp)tu,laq){ueu alenrltetsnul uor}eulo;suell)tloqp}aulV'uotle^tl)pua6our:re1(V).suo6ou!)Je)u/vlouleuo5 77*97e.rn613vNc NtlNtNVn901 cNnoS NlgONtfuv)ICtXOdt-E',Z-NtXO-LV]lVNIXO.LVIIV(v)INggp-6auorqroy{rre)ue):g7ra1deq3gZC.l1227CAUSESOFCANCERTHEPREVENTABLECANCERTCANCERNO CANCERFigure20-23 Somepossibleschedulesof exposureto a tumor initiator(mutagenic.land a tumor Promoter(nonmutagr:nic)and their outcomes.Cancerensuesonly if the exposureto thepromoterfollowsexposureto theinitiatorand only if the intensityofexposureto the PromoterexceeosaCancercan alsooccurcertainthre:;hold.asa resultof repeatedexposureto theinitiatoralone.NO CANCER+TIICANCERcaused by a tumor initiator are irreversible; for this reason, they can be uncovered by treatment with a tumor promoter even after a long delay.It is still not certain how tumor promoters work, and different promoters arelikely to work in different ways.
One possibility is that they simply provoke theexpression of proliferation-inducing genes that had been mutated before thepromoter was applied but were not expressed:a mutation that makes a geneproduct hyperactive will not show its effects until the gene is expressed.Alternatively, the tumor promoter may temporarily alter the way the cell reactsto theproduct of the mutated gene, either by releasing the cell from a counteractinginhibitory influence or by triggering production of a co-factor necessaryfor proliferation of the mutated gene product.
lVhichever the mechanism, the result isthat the mutant cell is enabled to grow and divide and produce a large cluster ofcells (Figure 20-24).A tlpical papilloma might contain about 105cells. If exposure to the tumorpromoter is stopped, almost all the papillomas regress,and the skin regains alargely normal appearance.In a few of the papillomas, however, further changesoccur that enable cell growth and division to continue in an uncontrolled way,even after the promoter has been withdrawn. These changes seem to originatein an occasional single papilloma cell, at about the frequency expectedfor spontaneous mutations. In this way, a small proportion of the papillomas progresstobecome cancers.Thus, the tumor promoter apparently favors the developmentof cancer by expanding the population of cells that carry an initial mutation: themore such cells there are and the more times they divide, the greater is thechance that at least one of them will sustain another mutation, or an epigeneticchange, that carries it one step further toward malignancy.Although naturally occurring cancers do not necessarily arise through thespecific sequenceof distinct initiation and promotion stepsjust described, theirevolution must be governed by similar principles.
![](https://s.studizba.com/z.php?f=/templates/si/i/noavatar.png&w=100&h=100&t=1"){kind=avatar}
