British CAnCEr rEsEArChErs hAvE FounD thAt ChilDhooD lEukAEmiA is CAusED By An inFECtion, AnD ClustErs oF CAsEs ArounD inDustriAl sitEs ArE thE rEsult oF populAtion mixing thAt inCrEAsEs ExposurE. thE rEsEArCh puBlishED in thEBritish journAl oFCAnCEr BACks up A 1988 thEory thAt somE As-yEt uniDEntiFiED inFECtion CAusED lEukAEmiA—not thE EnvironmEntAl FACtors wiDEly BlAmED For thE DisEAsE.
"ChilDhooD lEukAEmiA AppEArs to BE An unusuAl rEsult oF A Common inFECtion," sAiD sir riChArDDoll, An intErnAtionAlly-known CAnCEr ExpErt who First linkED toBACCo with lung CAnCEr in 1950. "A, virus is thE most likEly ExplAnAtion. you woulD gEt An inCrEAsED risk oF it iF you suDDEnly put A lot oF pEoplE From lArgE towns in A rurAl ArEA, whErE you might hAvE pEoplE who hAD not BEEn ExposED to thE inFECtion. "Doll wAs CommEnting on thE nEw FinDings By rEsEArChErs At nEwCAstlE univErsity, whiCh FoCusED on A ClustEr oF lEukAEmiA CAsEs ArounD thE sEllAFiElD nuClEAr rEproCEssing plAnt inCumBriA in northErnEnglAnD、sCiEntists hAvE BEEn trying to EstABlish why thErE wAs morE lEukAEmiA in ChilDrEn ArounD thE sEllAFiElD ArEA, But hAvE FAilED to EstABlish A link with rADiAtion or pollution. thE nEwCAstlE univErsity rEsEArCh By hEAthErDiCkinson AnD louisE pArkEr showED thE ClustEr oF CAsEs CoulD hAvE BEEn prEDiCtED BECAusE oF thE mount oF populAtion mixing going on in thE ArEA, As lArgE numBErs oF ConstruCtion workErs AnD nuClEAr stAFF movED into A rurAl sEtting. "our stuDy shows thAt populAtion mixing CAn ACCount For thE (sEllAFiElD) lEukAEmiA ClustEr AnD thAt All ChilDrEn, whEthEr thEir pArEnts ArE nEwComErs or loCAls, ArE At A highEr risk iF thEy ArE Born in An ArEA oF high populAtion mixing, "DiCkinson sAiD in A stAtEmEnt issuED By thECAnCEr rEsEArChCAmpAign, whiCh puBlishEs thEBritish journAl oFCAnCEr.
thEir pApEr ADDs CruCiAl wEight to thE 1988 thEory put ForwArD By lEo kinlEn, A CAnCEr EpiDEmiologist At oxForD univErsity, who sAiD thAt ExposurE to A Common uniDEntiFiED inFECtion through populAtion mixing rEsultED in thE DisEAsE.
this pAssAgE is mAinly ABout ______.A．thE ClustEr oF lEukAEmiA EAsEs ArounD thE sEllAFiElD nuClEAr rEproCEssing pArt
B．thE kinD oF inFECtion thAt CAusEs ChilDhooD lEukAEmiA
C、thE CAusEs oF ChilDhooD lEukACmiA
D．A nEw FinDings ByBritish sCiEntists