Johns Hopkins Kimmel Kanser Merkezi\u2019nden biliminsanlar\u0131, bir\u00e7ok doku tipinde k\u00f6k h\u00fccrelerin b\u00f6l\u00fcnmesi s\u0131ras\u0131nda, daha \u00e7ok rasgele mutasyonlar nedeniyle ortaya \u00e7\u0131kan kanser insidans (belirli bir hastal\u0131kta yeni olgu say\u0131s\u0131) oran\u0131n\u0131 \u00f6l\u00e7en bir istatistik model olu\u015fturdu. \u00d6l\u00e7\u00fcmlere g\u00f6re, eri\u015fkin kanser insidans\u0131n\u0131n 2\/3\u2019l\u00fck b\u00f6l\u00fcm\u00fc rasgele mutasyonlar sonucu ortaya \u00e7\u0131kan \u201ck\u00f6t\u00fc \u015fans\u201d ile a\u00e7\u0131klanabilirken, kalan 1\/3\u2019l\u00fck b\u00f6l\u00fcm\u00fc \u00e7evresel fakt\u00f6rlere ve kal\u0131tsal genlere ba\u011flanmaktad\u0131r.
\nJohns Hopkins \u00dcniversitesi T\u0131p Fak\u00fcltesi\u2019nde Clayton Onkoloji Profes\u00f6r\u00fc, Johns Hopkins Ludwig Merkezi Y\u00f6netici Yard\u0131mc\u0131s\u0131 ve Howard Hughes T\u0131p Enstit\u00fcs\u00fc\u2019nde ara\u015ft\u0131rmac\u0131 olarak \u00e7al\u0131\u015fan Dr. Bert Vogelstein yapt\u0131\u011f\u0131 a\u00e7\u0131klamada, \u201cT\u00fcm kanserler \u2018k\u00f6t\u00fc \u015fans\u2019, \u00e7evresel ve kal\u0131t\u0131msal fakt\u00f6rlerin kombinasyonu sonucu olu\u015fur ve biz bu \u00fc\u00e7 fakt\u00f6r\u00fcn kanser geli\u015fimine ne kadar katk\u0131s\u0131 oldu\u011funu \u00f6l\u00e7meye yard\u0131mc\u0131 olacak bir model olu\u015fturduk\u201d dedi.
\nT\u00fct\u00fcn gibi kansere neden olan maddelere maruz kalan ki\u015filerde kansersiz ya\u015fam\u0131n, s\u0131k s\u0131k \u201ciyi genler\u201d ile a\u00e7\u0131klanmakla birlikte, ger\u00e7ekte bu insanlar\u0131n \u00e7o\u011funun sadece \u015fansl\u0131 oldu\u011funu belirten Vogelstein, k\u00f6t\u00fc ya\u015fam ko\u015fullar\u0131n\u0131n da kanser geli\u015fimine \u201ck\u00f6t\u00fc \u015fans\u201d fakt\u00f6r\u00fc olarak katk\u0131s\u0131 olabilece\u011fini ekledi.
\nJohns Hopkins \u00dcniversitesi T\u0131p Fak\u00fcltesi ve Bloomberg Halk Sa\u011fl\u0131\u011f\u0131 Okulu\u2019nda Onkoloji Yard. Do\u00e7enti ve Biyomatematik\u00e7i Dr. Cristian Tomasetti\u2019ye g\u00f6re, geli\u015ftirdikleri modelin, kamuoyunda kanser risk fakt\u00f6rleri alg\u0131s\u0131n\u0131 de\u011fi\u015ftirmekten kanser ara\u015ft\u0131rmalar\u0131n\u0131n finasman\u0131na kadar bir\u00e7ok etkisi olabilir. \u201cE\u011fer dokularda kanser insidans\u0131n\u0131n 2\/3\u2019\u00fc k\u00f6k h\u00fccre b\u00f6l\u00fcnmesi s\u0131ras\u0131nda ortaya \u00e7\u0131kan rasgele DNA mutasyonlar\u0131 ile a\u00e7\u0131klanabiliyorsa, ya\u015fam tarz\u0131 ve al\u0131\u015fkanl\u0131klar\u0131m\u0131z\u0131 de\u011fi\u015ftirmek baz\u0131 kanser t\u00fcrlerinin \u00f6nlenmesine \u00e7ok yard\u0131mc\u0131 olacakt\u0131r. Biz daha \u00e7ok bu t\u00fcr kanserlerin erken ve tedavi edilebilir evrelerde tan\u0131 konulmas\u0131na y\u00f6nelik ara\u015ft\u0131rmalara odaklanmal\u0131y\u0131z\u201d dedi.
\nScience dergisinin 2 Ocak tarihli bask\u0131s\u0131nda istatistiksel sonu\u00e7lar\u0131n\u0131 yay\u0131mlayan Tomasetti ve Vogelstin, ortalama bir bireyin ya\u015fam\u0131 s\u0131ras\u0131nda 31 doku t\u00fcr\u00fcndeki k\u00f6k h\u00fccre b\u00f6l\u00fcnmelerinin k\u00fcm\u00fclatif toplam\u0131 hakk\u0131nda yay\u0131mlanan bilimsel literat\u00fcr\u00fc ara\u015ft\u0131rarak bu sonuca vard\u0131klar\u0131n\u0131 belirttiler. K\u00f6k h\u00fccreler, \u201ckendini yeniler\u201d, dolay\u0131s\u0131yla spesifik bir organda \u00f6len h\u00fccrelerin yerine ge\u00e7erler.
\nDoku-spesifik k\u00f6k h\u00fccrelerdeki b\u00f6l\u00fcnme s\u0131ras\u0131nda, DNA replikasyonu a\u015famas\u0131nda g\u00f6r\u00fclen rastgele hatalar veya mutasyonlar sonucu kanserin ortaya \u00e7\u0131kt\u0131\u011f\u0131 iyi bilinmektedir. Bu mutasyonlar biriktik\u00e7e, h\u00fccrelerin kontrolsuz b\u00fcy\u00fcme riski de artacakt\u0131r, ki bu durum kanserin ay\u0131rt edici bir \u00f6zelli\u011fidir. Bu rasgele hatalar\u0131n kanser insidans\u0131na olan ger\u00e7ek katk\u0131s\u0131, kal\u0131tsal veya \u00e7evresel fakt\u00f6rlerin katk\u0131s\u0131 ile kar\u015f\u0131la\u015ft\u0131r\u0131ld\u0131\u011f\u0131nda, daha \u00f6nceden bilinmemekteydi.
\nBu t\u00fcr rasgele mutasyonlar\u0131n kanser geli\u015fme riskindeki rol\u00fcn\u00fc anlamak i\u00e7in, Johns Hopkins biliminsanlar\u0131 31 dokudaki k\u00f6k h\u00fccre b\u00f6l\u00fcnme say\u0131s\u0131n\u0131 hesaplad\u0131lar ve bu oranlar\u0131 Amerikal\u0131lar aras\u0131nda ayn\u0131 dokularda g\u00f6r\u00fclen ya\u015fam boyu kanser riskiyle kar\u015f\u0131la\u015ft\u0131rd\u0131lar. Ba\u011f\u0131ms\u0131z de\u011fi\u015fkenler aras\u0131ndaki ili\u015fkiyi g\u00f6steren serpilme grafi\u011fine (scatterplot) bak\u0131ld\u0131\u011f\u0131nda, k\u00f6k h\u00fccre b\u00f6l\u00fcnme say\u0131s\u0131 ve kanser riski aras\u0131ndaki korelasyon 0, 804 olarak hesapland\u0131. Matematiksel olarak, hesaplanan de\u011fer 1\u2019e ne kadar yak\u0131nsa, k\u00f6k h\u00fccre b\u00f6l\u00fcnmesi ve kanser riski aras\u0131ndaki korelasyon o kadar g\u00fc\u00e7l\u00fcd\u00fcr.
\n\u201c\u00c7al\u0131\u015fmam\u0131z, bir doku tipindeki k\u00f6k h\u00fccre b\u00f6l\u00fcnme say\u0131s\u0131ndaki de\u011fi\u015fmenin, ayn\u0131 dokudaki kanser insidans oran\u0131ndaki de\u011fi\u015fim ile ba\u011flant\u0131l\u0131 oldu\u011funu genel olarak g\u00f6stermi\u015ftir\u201d diyor Vogelstein. \u00d6rnek olarak kolon dokusunda ince ba\u011f\u0131rsak dokusuna oranla d\u00f6rt kat daha fazla k\u00f6k h\u00fccre b\u00f6l\u00fcnmesi g\u00f6r\u00fcl\u00fcr. Keza, kolon kanseri ince ba\u011f\u0131rsak kanserinden \u00e7ok daha s\u0131k g\u00f6r\u00fclmektedir.
\n\u0130nce ba\u011f\u0131rsak ile kar\u015f\u0131la\u015ft\u0131r\u0131ld\u0131\u011f\u0131nda, kolonun daha fazla \u00e7evresel fakt\u00f6re maruz kald\u0131\u011f\u0131 \u00f6ne s\u00fcr\u00fclebilir. Fakat, bu bulgular\u0131n tam tersine biliminsanlar\u0131, fare kolonunda k\u00f6k h\u00fccre b\u00f6l\u00fcnmesinin ince ba\u011f\u0131rsa\u011fa g\u00f6re daha az oldu\u011funu ve kanser insidans\u0131n\u0131n ince ba\u011f\u0131rsak ile kar\u015f\u0131la\u015ft\u0131r\u0131ld\u0131\u011f\u0131nda kolonda daha az oldu\u011funu tespit ettiler. Bu bulgular, kanser geli\u015fiminde toplam k\u00f6k h\u00fccre b\u00f6l\u00fcnme say\u0131s\u0131n\u0131n anahtar rol\u00fcn\u00fc desteklemektedir. \u0130statistiksel teori kullan\u0131larak, kanser risk varyasyon hesaplamas\u0131 k\u00f6k h\u00fccre b\u00f6l\u00fcnme say\u0131s\u0131 ile a\u00e7\u0131klanabilir, ki bu say\u0131 0, 804\u2019\u00fcn karesi veya y\u00fczde 65\u2019tir.
\nSon olarak, ara\u015ft\u0131rmac\u0131 ikili, kanser t\u00fcrlerini iki grupta s\u0131n\u0131fland\u0131rd\u0131. Hangi kanser t\u00fcrleri insidans\u0131n\u0131n k\u00f6k h\u00fccre b\u00f6l\u00fcnme say\u0131s\u0131 ile tahmin edilebilece\u011fini ve hangilerinin daha y\u00fcksek insidansa sahip oldu\u011funu istatistiksel olarak hesaplad\u0131lar. 22 kanser t\u00fcr\u00fcn\u00fcn b\u00fcy\u00fck \u00f6l\u00e7\u00fcde h\u00fccre b\u00f6l\u00fcnmesi s\u0131ras\u0131nda ortaya \u00e7\u0131kan rasgele DNA mutasyonlar\u0131na ba\u011fl\u0131 \u201ck\u00f6t\u00fc \u015fans\u201d fakt\u00f6r\u00fc ile a\u00e7\u0131klanabilece\u011fini, di\u011fer dokuz kanser t\u00fcr\u00fcn\u00fcn ise \u201ck\u00f6t\u00fc \u015fans\u201d ile a\u00e7\u0131klanandan daha y\u00fcksek bir insidansa sahip oldu\u011fu ve k\u00f6t\u00fc \u015fans, \u00e7evresel ve kal\u0131tsal fakt\u00f6rlerin kombinasyonuna ba\u011fl\u0131 olabilece\u011fini \u00f6ne s\u00fcrd\u00fcler.
\nDr. Vogelstein, k\u00f6k h\u00fccre b\u00f6l\u00fcnme say\u0131s\u0131na g\u00f6re tahmin edilenden daha y\u00fcksek riske sahip olan kanser t\u00fcrlerinin, beklendi\u011fi gibi sigara ile ili\u015fkili akci\u011fer kanseri, g\u00fcne\u015fe maruz kalma ile ili\u015fkili cilt kanseri ve kal\u0131tsal sendromlarla ili\u015fkili kanserler oldu\u011funu belirtti.
\nBu \u00e7al\u0131\u015fma g\u00f6steriyor ki, sigara veya k\u00f6t\u00fc ya\u015fam tarz\u0131 gibi fakt\u00f6rler kansere yakalanma riskine katk\u0131da bulunabilir. Ancak, bir\u00e7ok kanser t\u00fcr\u00fc, ya\u015fam tarz\u0131 ve kal\u0131tsal fakt\u00f6rlerden ba\u011f\u0131ms\u0131z olarak kansere neden olan genlerdeki kazan\u0131lm\u0131\u015f mutasyon kaynakl\u0131 k\u00f6t\u00fc \u015fanstan kaynaklanmaktad\u0131r. Bu kanserleri ortadan kald\u0131rman\u0131n en iyi yolu ameliyatla tedavi edilebilir bir evrede iken erken tan\u0131 sayesinde olacakt\u0131r.
\nBiliminsanlar\u0131, meme ve prostat kanseri gibi baz\u0131 kanser t\u00fcrlerinin \u00e7al\u0131\u015fmaya dahil edilmedi\u011fini, \u00e7\u00fcnk\u00fc bilimsel literat\u00fcrde bu kanser t\u00fcrlerinin k\u00f6k h\u00fccre b\u00f6l\u00fcnme oranlar\u0131 ile ilgili g\u00fcvenilir bir kaynak bulamad\u0131klar\u0131n\u0131 ve ba\u015fka ara\u015ft\u0131rmac\u0131lar\u0131n daha hassas k\u00f6k h\u00fccre b\u00f6l\u00fcnme oranlar\u0131n\u0131 bularak kendi istatistiksel modellerini geli\u015ftirmeyi umduklar\u0131n\u0131 belirttiler. <\/p>\n
\u00c7eviren: Dr. Serta\u00e7 Yaz\u0131c\u0131 Kaynak:<\/strong> http:\/\/www.sciencedaily.com\/releases\/2015\/01\/150101142318.htm Johns Hopkins Kimmel Kanser Merkezi\u2019nden biliminsanlar\u0131, bir\u00e7ok doku tipinde k\u00f6k h\u00fccrelerin b\u00f6l\u00fcnmesi s\u0131ras\u0131nda, daha \u00e7ok rasgele mutasyonlar nedeniyle ortaya \u00e7\u0131kan kanser insidans (belirli bir hastal\u0131kta yeni olgu say\u0131s\u0131) oran\u0131n\u0131 \u00f6l\u00e7en bir istatistik model olu\u015fturdu. \u00d6l\u00e7\u00fcmlere g\u00f6re, eri\u015fkin kanser insidans\u0131n\u0131n 2\/3\u2019l\u00fck b\u00f6l\u00fcm\u00fc rasgele mutasyonlar sonucu ortaya \u00e7\u0131kan \u201ck\u00f6t\u00fc \u015fans\u201d ile a\u00e7\u0131klanabilirken, kalan 1\/3\u2019l\u00fck b\u00f6l\u00fcm\u00fc \u00e7evresel fakt\u00f6rlere […]<\/p>\n","protected":false},"author":1,"featured_media":1701,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[19,231,33],"tags":[],"class_list":["post-1700","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-bilim-gundemi","category-molekuler-biyoloji-ve-genetik","category-saglik-bilimleri"],"acf":[],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/bilimvegelecek.com.tr\/index.php\/wp-json\/wp\/v2\/posts\/1700","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/bilimvegelecek.com.tr\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/bilimvegelecek.com.tr\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/bilimvegelecek.com.tr\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/bilimvegelecek.com.tr\/index.php\/wp-json\/wp\/v2\/comments?post=1700"}],"version-history":[{"count":0,"href":"https:\/\/bilimvegelecek.com.tr\/index.php\/wp-json\/wp\/v2\/posts\/1700\/revisions"}],"wp:attachment":[{"href":"https:\/\/bilimvegelecek.com.tr\/index.php\/wp-json\/wp\/v2\/media?parent=1700"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/bilimvegelecek.com.tr\/index.php\/wp-json\/wp\/v2\/categories?post=1700"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/bilimvegelecek.com.tr\/index.php\/wp-json\/wp\/v2\/tags?post=1700"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
\nOspedale San Bassiano, Vicenza, \u0130talya<\/strong><\/em><\/p>\n
\nDergi referans\u0131:<\/strong> C. Tomasetti, B. Vogelstein; \u201cVariation in cancer risk among tissues can be explained by the number of stem cell divisions\u201d, Science, 2015; 347 (6217): 78 DOI: 10.1126\/science.1260825<\/p>\n","protected":false},"excerpt":{"rendered":"