【癌症病因】2/3的癌症真的只是运气不好？
A recent paper does not show that two-thirds of cancer cases are due to bad luck
近期的研究报告其实并未证明三分之二的癌症病例是运气不好所致
译者：深秋の黎明
WHAT could be more welcome in a season that demands fresh starts, abstinence and “detoxing” than to discover that you do not have to lift a finger to avoid cancer? A paper published last week in Science seemed to offer seasonal bingers every reason for ripping up their New Year’s resolutions. According to many reports of the research, it suggested two-thirds of human cancers are caused by nothing more than bad luck.
在一个需要崭新开始、清心寡欲、“排毒养颜”的圣诞节，还有什么能比轻而易举就能预防癌症这一发现更令人愉快的？本周《科学》杂志发表的一篇研究报告给了圣诞吃货们充分理由放弃他们的新年决心。该研究的多篇报告表明，三分之二的人类癌症纯属运气不好所致。
Clean-living folk will be pleased to hear that the scientists concerned are saying nothing of the sort. One of the paper’s authors, Cristian Tomasetti of Johns Hopkins University, was happy to clarify: “We have not showed that two-thirds of cancer cases are about bad luck. Cancer is in general a combination of bad luck, bad environment and bad inherited genes.”
听说有关科学家从未这样说过，洁身自好的人肯定会感到开心。约翰·霍普金斯大学的克里斯蒂安·托马塞蒂是该报告的作者之一，他高兴地澄清说：“我们从未表示三分之二的癌症病例是运气不好所致。通常来讲，癌症是糟糕运气、恶劣环境、不良遗传基因的合力结果”。
Dr Tomasetti and his colleague Bert Vogelstein were looking at why cancers are more frequent in some parts of the body than in others. They wanted to know if the rate was related to the frequency with which cells in these tissues divide. Every time a cell replicates there is a chance of a mutation. More divisions means more mutations and perhaps more cancers.
托马塞蒂博士和他的同事伯特·福格斯坦正在研究为何某些身体部位的癌症发病率更高，这是否与组织细胞的分裂频率有关。细胞的每次复制都有可能发生变异，细胞分裂越频繁，发生变异和癌症的可能性就越大。
Organs renew themselves from special cells called stem cells that, when they divide, produce one daughter cell which is another stem cell, and a second which goes on to generate descendants that are cells needed by the tissue in question. Dr Tomasetti and Dr Vogelstein plotted the average number of times a stem cell divides during the course of a lifetime in 31 types of tissue against the lifetime risks of cancer developing in those tissues. They found a strong correlation.
人体器官通过特殊的“干细胞”进行自我更新，干细胞能分裂出一个子代干细胞，以此连续不断的分裂出组织需要的干细胞。托马塞蒂博士和福格斯坦博士将31种组织干细胞的终生平均分裂次数与这些组织的终生患癌风险进行对比后发现，两者之间存在紧密联系。
The results indicate that two-thirds of the variation in cancer risk between different tissues is caused by chance mutations associated with cell division. This is not the same as saying that two-thirds of cancer cases are caused by chance, because the results do not offer any information about the relative rates of occurrence of the cancers in question. Moreover, Dr Tomasetti and Dr Vogelstein were unable to include two of the most common cancers (breast and prostate) in their analysis, because the relevant stem-cell data are not available for these. What their study does explain is the long-known but curious phenomenon that apparently similar parts of the body suffer different rates of cancer. Stem-cell turnover means, for example, that tumours of the large intestine are commoner than those of the small one, while basal-cell carcinomas in the skin are commoner than melanomas.
研究结果表明，与细胞分裂有关的偶然变异造成了人体各组织三分之二的癌症风险差异。这并不是说三分之二的癌症病例是偶然发生的，因为研究结果并未提供癌症相对发生率的有关信息。而且托马塞蒂博士和福格斯坦博士在分析中无法涵盖最普遍的乳腺癌和前列腺癌，因为目前缺少这两处组织的干细胞数据。他们的研究解释了一个早已为人所知的奇特现象，即明显类似的人体部位具有不同的癌症发病率。例如，干细胞的分裂频率意味着大肠肿瘤的发生率高于小肠，皮肤基底细胞癌发生率高于黑色素瘤。
None of this, though, is reason for fatalism. Copying errors during cell division are by no means the only source of cancer-causing mutations. Chemicals that damage DNA, ultraviolet light, ionising radiation and viral infections are all culprits too—and culprits that can often be avoided by thoughtful behaviour.
这些都不足以支持宿命论。细胞在分裂期间复制错误绝不是致癌变异的唯一原因，化学物质会对DNA造成损害，紫外线光、离子化辐射、病毒感染也是罪魁祸首，人类通过慎重行为往往能够避免这些因素。
Overall, according to research done in Britain by Cancer Research UK, a charity, 42% of cancer cases are tied to factors within an individual’s control. These include smoking (which, through the carcinogenic chemicals it creates, causes 86% of lung cancer, 65% of oesophageal cancer, 37% of bladder cancer and 29% of pancreatic cancer), poor diet (51% of stomach cancer and 56% of head and neck cancer), overexposure to sunlight (86% of malignant melanomas) and infection with papilloma virus (almost 100% of cervical cancer). Obesity, alcohol and lack of exercise are also in the frame. The best advice, then, remains: keep slathering on the sun cream, avoid tobacco smoke, eat and drink well, exercise regularly and, if you are a young woman, have an anti-papilloma vaccination.
总的来说，“英国癌症研究中心”慈善机构研究表明：42%的癌症病例与个人自身的可控因素有关，包括吸烟（吸烟产生的致癌化学物质导致了86%肺癌、65%食道癌、37%膀胱癌、29%胰腺癌），不良饮食（导致了51%胃癌、56%头颈癌），皮肤过度暴露在阳光下（导致了86%恶性黑色素瘤），乳头瘤病毒感染（几乎100%导致子宫颈癌）。另外，肥胖、酗酒、缺乏运动也位列其中。所以最好的建议还是：为皮肤涂上厚厚的防晒霜，避免吸烟喝酒，坚持定期运动。另外，年轻女性还须注射乳头瘤病毒预防疫苗。
remark:【辟谣】所谓2/3的癌症是运气不好，其实是误读。约翰·霍普金斯大学的克里斯蒂安·托马塞蒂是该报告的作者之一，他高兴地澄清说：“我们从未表示三分之二的癌症病例是运气不好所致。通常来讲，癌症是糟糕运气、恶劣环境、不良遗传基因的合力结果”
2/ 那他们到底研究的是啥？托马塞蒂博士和他的同事伯特·福格斯坦正在研究为何某些身体部位的癌症发病率更高，这是否与组织细胞的分裂频率有关。细胞的每次复制都有可能发生变异，细胞分裂越频繁，发生变异和癌症的可能性就越大
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