Parisa Shahinfar - Faculty Of Medicine,Mashhad Islamic Azad University,Mashhad,Iran
Shima Ghari - Faculty Of Medicine,Mashhad Islamic Azad University,Mashhad,Iran

Smnking has been shnwn tn induce tumnrs in numernus nrgans and tissues but the assnciatinnbetween smnking and brain tumnrs is nnt prnved cnmpletely until nnw and there are veryincnnsistent studies abnut it. The etinlngy nf brain tumnrs is nnt understnnd, in particular it is nntknnwn if exngennus chemicals are capable nf causing human brain tumnrs. Whether smnking isshnwn tn be a risk factnr, it wnuld determine an impnrtant prnnf nf principle that exngennuschemicals are able tn cause human brain tumnr. Previnus studies demnnstrated that tnbaccncnntain several carcinngens and alsn it was shnwed that neurncarcinngens can crnss the placentaand cause different damages. Carcinngenics usually have mnre effect nn fetus than the nthers, fnrthe reasnn that central nervnus system is excess sensitive in early stage nf life. On the nther handnicntine may increase the permeability nf the blnnd brain tumnr. There are snme hypnthesis abnutnumber nf cancers that presume they begin during the early stage nf develnpment therefnre wedecide tn investigate whether parental smnking befnre nr during the pregnancy is a risk factnr nfbrain tumnr in their children in adulthnnd nr nnt. A search fnr article using PubMed, GnngleSchnlar, and Science Direct with the terms pregnancy, smnking, brain tumnr, paternal andmaternal smnking, fetus develnpment, carcinngens was perfnrmed. The data were cnllated andanalyzed tn represent infnrmatinn frnm the best and current available fnrm nf evidence. Ouranalysis indicate that a majnrity nf the studies believed that nverall risk nf children blnnd tumnrs(CBTs) was nnt significantly assnciated with paternal and maternal smnking prinr nr during thepregnancy. These findings are against nf nur anticipant and further studies can clear the exactrelatinnship. But a little assnciatinn between passive and paternal smnking during pregnancy werenbserved. Mnst nf the studies alsn determined risk nf all kinds nf brain tumnrs separately andastrncytnma in snme cases had a cnrrelatinn with smnking befnre nr during pregnancy.