美国国家公共电台 NPR Cancer Is Partly Caused By Bad Luck, Study Finds

 

KELLY MCEVERS, HOST:

There are a lot of reasons why people get cancer. Sometimes it's exposure to something toxic¹ like smoke. Sometimes it's just bad genes³. New research finds most of the genetic⁴ mutations that lead to cancer crop up naturally, and they're unavoidable. NPR's Richard Harris reports.

RICHARD HARRIS, BYLINE⁵: First the backstory - two years ago, Bert Vogelstein and Cristian Tomasetti at Johns Hopkins University started controversy⁶ by suggesting that many cancers are unavoidable. Critics said that was undercutting the message that many cancers are preventable. So when these scientists had new results to report, Vogelstein made that point absolutely clear.

(SOUNDBITE OF PRESS CONFERENCE)

BERT VOGELSTEIN: We all agree that 40 percent of cancers are preventable. The question is, what about the other cancers that aren't known to be preventable?

HARRIS: Speaking at a news conference, Dr. Vogelstein and his colleague explained how they have now refined that question.

(SOUNDBITE OF PRESS CONFERENCE)

VOGELSTEIN: Every time a perfectly⁷ normal cell divides, it makes several mistakes, mutations.

HARRIS: Most of the time, those mutations are in unimportant bits of DNA⁸. That's good luck.

(SOUNDBITE OF PRESS CONFERENCE)

VOGELSTEIN: But occasionally they occur in a cancer driver gene². That's bad luck.

HARRIS: After two or three of these driver genes get mutated in the same cell, the cell can turn cancerous. In their new paper in Science, the researchers set out to quantify how often these mutations are random⁹ errors that result from cell division, how often they're caused by nasty chemicals like tobacco smoke and how often they're inherited.

(SOUNDBITE OF PRESS CONFERENCE)

VOGELSTEIN: Sixty-six percent of the total mutations are random, about 29 percent due to the environment and the remaining 5 percent due to heredity.

HARRIS: These numbers depend on the type of cancer. Lung cancer is largely triggered by environmental causes - smoking - while the vast majority of childhood cancer is a result of these bad luck mutations. Right now, Vogelstein says parents who focus on environment and heredity are likely to think they are somehow responsible for their child's disease - not so.

(SOUNDBITE OF PRESS CONFERENCE)

VOGELSTEIN: They need to understand that these cancers would have occurred no matter what they did. We don't need to add guilt¹⁰ to an already tragic¹¹ situation.

HARRIS: Of course people can reduce their risk of preventable cancer by avoiding tobacco and eating well. As for the mutations that occur spontaneously...

(SOUNDBITE OF PRESS CONFERENCE)

VOGELSTEIN: Now, what can people do - nothing - right now, nothing. This is a question for research.

HARRIS: In fact the paper raises many questions. Martin Novak is a biologist and mathematician¹² at Harvard.

MARTIN NOVAK: The question is super fascinating. So the question is really, how much of human cancer is caused by bad luck? How much is caused by bad things that we do? The question is super fascinating.

HARRIS: He says the new findings are provoking discussion among cancer scientists, and that's all for the good.

NOVAK: How exactly we can actually answer these questions? It is very unclear to me whether we have the tools in hand right now.

HARRIS: So you don't expect this paper to put to rest the controversy that the first one stirred up.

NOVAK: No, I think it will raise an even bigger controversy.

HARRIS: One of the big sticking point is that mutations, while necessary, aren't the whole story. Dr. Graham Colditz at Washington University in St. Louis isn't convinced that hazards have been neatly¹³ sorted into the categories of heredity, environment and unavoidable mutations.

GRAHAM COLDITZ: How these interplay with each other I think is still potentially more complex.

HARRIS: Vogelstein and Tomasson (ph) are prepared to argue these matters with their colleagues, and on one point at least they do agree. While mutations are necessary for cancer, they don't entirely¹⁴ explain why some mutated cells eventually become aggressive, deadly cancers and others don't. Richard Harris, NPR News.

(SOUNDBITE OF BADBADNOTGOOD SONG, "CONFESSIONS")

1 toxic   

adj.有毒的，因中毒引起的

参考例句：

• The factory had accidentally released a quantity of toxic waste into the sea.这家工厂意外泄漏大量有毒废物到海中。
• There is a risk that toxic chemicals might be blasted into the atmosphere.爆炸后有毒化学物质可能会进入大气层。

2 gene   

n.遗传因子，基因

参考例句：

• A single gene may have many effects.单一基因可能具有很多种效应。
• The targeting of gene therapy has been paid close attention.其中基因治疗的靶向性是值得密切关注的问题之一。

3 genes   

n.基因( gene的名词复数 )

参考例句：

• You have good genes from your parents, so you should live a long time. 你从父母那儿获得优良的基因，所以能够活得很长。 来自《简明英汉词典》
• Differences will help to reveal the functions of the genes. 它们间的差异将会帮助我们揭开基因多种功能。 来自英汉非文学 - 生命科学 - 生物技术的世纪

4 genetic   

adj.遗传的，遗传学的

参考例句：

• It's very difficult to treat genetic diseases.遗传性疾病治疗起来很困难。
• Each daughter cell can receive a full complement of the genetic information.每个子细胞可以收到遗传信息的一个完全补偿物。

5 byline   

n.署名；v.署名

参考例句：

• His byline was absent as well.他的署名也不见了。
• We wish to thank the author of this article which carries no byline.我们要感谢这篇文章的那位没有署名的作者。

6 controversy   

n.争论，辩论，争吵

参考例句：

• That is a fact beyond controversy.那是一个无可争论的事实。
• We ran the risk of becoming the butt of every controversy.我们要冒使自己在所有的纷争中都成为众矢之的的风险。

7 perfectly   

adv.完美地，无可非议地，彻底地

参考例句：

• The witnesses were each perfectly certain of what they said.证人们个个对自己所说的话十分肯定。
• Everything that we're doing is all perfectly above board.我们做的每件事情都是光明正大的。

8 DNA   

(缩)deoxyribonucleic acid 脱氧核糖核酸

参考例句：

• DNA is stored in the nucleus of a cell.脱氧核糖核酸储存于细胞的细胞核里。
• Gene mutations are alterations in the DNA code.基因突变是指DNA密码的改变。

9 random   

adj.随机的；任意的；n.偶然的(或随便的)行动

参考例句：

• The list is arranged in a random order.名单排列不分先后。
• On random inspection the meat was found to be bad.经抽查，发现肉变质了。

10 guilt   

n.犯罪；内疚；过失，罪责

参考例句：

• She tried to cover up her guilt by lying.她企图用谎言掩饰自己的罪行。
• Don't lay a guilt trip on your child about schoolwork.别因为功课责备孩子而使他觉得很内疚。

11 tragic   

adj.悲剧的，悲剧性的，悲惨的

参考例句：

• The effect of the pollution on the beaches is absolutely tragic.污染海滩后果可悲。
• Charles was a man doomed to tragic issues.查理是个注定不得善终的人。

12 mathematician   

n.数学家

参考例句：

• The man with his back to the camera is a mathematician.背对着照相机的人是位数学家。
• The mathematician analyzed his figures again.这位数学家再次分析研究了他的这些数字。

13 neatly   

adv.整洁地，干净地，灵巧地，熟练地

参考例句：

• Sailors know how to wind up a long rope neatly.水手们知道怎样把一条大绳利落地缠好。
• The child's dress is neatly gathered at the neck.那孩子的衣服在领口处打着整齐的皱褶。

14 entirely   

ad.全部地，完整地；完全地，彻底地

参考例句：

• The fire was entirely caused by their neglect of duty. 那场火灾完全是由于他们失职而引起的。
• His life was entirely given up to the educational work. 他的一生统统献给了教育工作。