[2008.09.13] 良药：击杀癌症

Medicine
良药

Shooting down cancer
击杀癌症

Sep 11th 2008
From The Economist print edition

A theory linking the scourge to stem cells may offer new ways of treating this most terrifying of diseases
一个将病患与干细胞相连的理论也许会给最瘆人的疾病提供一个新的解决之道

EVERY age is afraid of plagues. For the most part, such plagues have been infections. The rich world, though, has brought infectious disease under control and, AIDS aside, the memory dims with every generation. Instead, the fear of disease has transferred itself to cancer. How to prevent it, and how to treat it if prevention has failed, fills the health pages of the newspapers. How this or that celebrity won or lost his or her battle with it seems to fill much of the rest.
每一个时代都一样的惧怕瘟疫，多半是因为瘟疫具有传染性。尽管富裕国家已经对传染性疾病具备了先当的控制力，当然艾滋病要暂时撇开不谈，恐怖的记忆逐渐淡去；但是对于疾病的恐惧已经转移到了癌症上。所有的报刊健康版面上都充斥着如何预防或者如何治疗癌症的文章，而其他的空间则写满了这个或是那个名人是如何在抗击癌症的过程中胜利或者失败的。

The military metaphor is not confined to newspapers. It is 37 years since Richard Nixon, then America’s president, declared war on the disease. During that time, the prognosis for cancer patients has got a lot better. Scientists have refined old therapies and found new ones. Moreover, governments have waged a relentless public-health campaign against the biggest cause of cancer-the smoking of tobacco. The war, however, has never looked close to being won. Scan the horizon and there is no sign of a cure.
用军事隐喻形容抗击癌症并仅仅停留在报刊上。美国总统理查德.尼克松宣布抗癌战争已经37年了，在这段时间里癌症病人得到了更好的预后。科学家们对既有的治疗方法进行了改进并且还发现了新疗法。政府更是毫不留情的资助了公众健康战争，对象是癌症的最大诱因–吸食烟草。但是似乎战争永远都不会趋近胜利；纵观全景，似乎都没有可以治愈癌症的迹象。

Nor is there likely to be until the enemy is properly understood. Though luck plays its part in medicine, as it does in warfare, the big breakthroughs usually come from dramatic shifts in understanding. It was not, for example, until Louis Pasteur and Robert Koch proved the connection between germs and infection that doctors realised that to cure such diseases you had to kill the germs. The germ theory of disease made sense of a collection of illnesses that obviously had things in common (a tendency to appear in waves, for example, or to pass from person to person) but were maddeningly different in their details. It took a while, but proof of that theory led to antibiotics that can destroy a whole range of infections.
而且在做到知己知彼以前也不可能有治愈的方法。尽管在药物领域中运气发挥着应有的作用，就像它们在战争中那样，但是重大突破往往出自理解力的巨大变化。举例来说，在路易斯巴斯德和罗伯特•考科证明了细菌与感染之间的必然联系以前，医生们都没有意识到只有杀死病毒才能治愈疾病。疾病细菌学说解释了为什么很多疾病有明显的共同之处(发生的趋势呈现出波状特点，例如通过人与人的传播)，但在细节上却相差甚远的原因。虽然花费了一定的时间，但是该理论的论证还是引领了抗生素的出现，相当多的传染病就此终结。

For cancer, a similar moment of enlightenment may now have arrived (see article). Like infections, cancers have prominent features in common, yet they are bafflingly different in their details. But, borrowing an idea from another part of biology, oncologists are coming to believe that most-possibly all-cancers involve stem cells, or something very like them. They are, in other words, caused and sustained by a small number of cells whose daughters grow into the tissue of a tumour rather as the daughters of healthy stem cells grow into the normal tissues that make up a body.
对癌症来说，目前似乎正处于类似的启蒙阶段：和传染病一样，不同的癌症在很多特征上表现出相当的共性，但是在细节上的不同却表现得令人费解。不过通过借用生物学其他分支的理念，肿瘤学家逐渐相信几乎全部的癌症都与干细胞或者极其类似干细胞的组织有关。换而言之，这些组织形成和持续存在的原因是一小部分细胞的子体成长为肿瘤组织；而健康细胞的子体应该成长为正常的组织，挺且构成了我们的躯体。

Patience, s’il vous plait
嘘。。。耐心些

This opens new ways of thinking about and treating the cancers. If its stem cells are eradicated, the rest of a tumour may die off. And if the secondary tumours-the truly feared killers in many forms of cancer-are the result of stem cells escaping from a primary tumour, as looks likely, then this knowledge may make them yield more easily to treatment.
该发现为研究和治疗癌症打开了了新思路：如果肿瘤的干细胞可以被根除，那么它本身也会随即死去。以各种形式癌症存在的次发性肿瘤才是真正令人可怖的杀手，它的成因看起来应该是干细胞从原发性肿瘤中游离出来的结果；如果真是这样，那么这个发现就会使肿瘤的治疗更加容易。

This discovery is not a cure. But it does point the way towards one-or, at the least, towards better therapies. Some might be in action soon. For example, it seems that cancer stem cells are less vulnerable to radiation than other cancer cells, because their DNA-repair mechanisms are better. Radiotherapy might thus be made more effective against them by dosing them with existing drugs that inhibit DNA repair. Some existing drugs which are known to interfere with stem cells’ biochemical pathways could be used to attack them selectively.
虽然这个发现并不是治愈的方法，但是却指明了找到根治癌症的方向，或者说至少可以带来更好的治疗方法。有些应该很快出现在实践中：例如癌症干细胞具有比其他的癌细胞更强的抗放射能力，因为它们的DNA修复机制更加健全。因此在针对癌症干细胞的治疗上，放射疗法的疗效就不如用一定剂量的现有药物来抑制NDA 的修复。一些现有药物可以阻碍干细胞的生化途径，因此可以选用这些药物来攻击肿瘤。

Other treatments will take far longer-the time needed for clinical trials would see to that and, in any case, a lot more research is in order. And there is the problem of designing drugs that can distinguish between cancer stem cells and those that spin off healthy tissues. But it all looks promising.
其他的治疗方法需要更长的时间–临床试验格外需要一些时间，但是很多的研发工作已经列入议事日程。设计出一个可以区分癌症干细胞和组成健康组织细胞的药物虽非易事，但是却颇有希望。

Blue sky ahead
灿烂前景

The other interesting aspect of the stem-cell link is that it was inspired by work outside the mainstream of the huge cancer-research industry: stem-cell research is now a huge field in its own right. In science you never know where the answer is going to come from. Pasteur found it in a piece of practical science: he was trying to prevent food going off. Charles Darwin, by contrast, found a lead for his theory of natural selection in the whimsical hobby of pigeon fancying, where the birds showed an enormous variety of form and behaviour. And some discoveries happen by accident. Radioactivity came to light a century after the discovery of uranium when Henri Becquerel used uranium salts and photographic plates in the same experiment and found that one fogged the other.
干细胞关联理论还有一个有趣的方面，它的启蒙来自于癌症主流研发历史以外的工作，而现在干细胞研究已经拥有了自己的巨大领域；在科学界里你永远都不悔之道答案竟来自何处。巴斯德在实用科学中发现了自己的理论：他当时正在尝试防止食物腐败。达尔文则相反，他自然选择的理论最初是在鸽子奇特习性中发现的，它们在行为方式上表现出巨大的变化。而有些发现是在偶然间发生的：在铀被发现后，放射学已经出现世纪有余；亨利•贝克勒尔使用铀盐和照相板做同样的试验的时候发现两者可以雾化在一起，于是铀出现了。

In the 19th century it was commonplace to do an experiment simply to see what would happen. That was, in part, because experimenters were often amateurs who were spending private money. In these days of taxpayer-financed science, most experiments are executed with a pretty clear idea of what the outcome ought to be, especially when they are part of wars and campaigns against this or that. The paradox is that, although such efforts do not eliminate Becquerel-like discoveries, they risk limiting the chances of making them.
在19世纪的日子里，单纯的为了观察结果而进行试验是稀松平常的，那是因为做试验的人都唱都是那些有闲钱可花的业余爱好者。而目前的试验投入都是纳税人的钱，所以大部分的试验只有在对结果又明确的的预期时才能实施，特别是试验成为对抗各种战争的组成部分的时候。矛盾之处在于，虽然这样的操作没有完全扼杀贝克勒尔式的发现，但是却大大限制了创造发现的机会。

This accent on targeted research is understandable. Plenty of the work now done on cancer will be of the targeted sort. The Large Hadron Collider, the huge particle accelerator in Switzerland which was switched on this week (see article), is a grand project that could yield all sorts of discoveries. Yet the easiest way to sell it to politicians was to frame it as a search for a single particle, the Higgs boson.
如此强调有目的性的研究是可以理解的：现在针对癌症展开的大量工作就是明确的目标。本周在瑞士启动的大型强子碰撞型加速装置是一个大型粒子加速器项目，该项目可能产生出很多的发现。当然将这个项目推销给政客的捷径是把它包装成为研究单一粒子的项目，希格斯玻色子。

Like natural selection and germs, the discovery of cancer stem cells illustrates how the most fruitful scientific findings are often not those of individual experiments, however intriguing, but those that organise knowledge into theory. The chemical industry took off within a decade or so of Dmitri Mendeleev’s arrangement of the chemical elements into the periodic table, just as radio communications followed James Clerk Maxwell’s mathematical unification of electricity and magnetism, and antibiotics came after Pasteur and Koch.
一如自然选择法则和病毒理论，癌症干细胞的发现验证了多产的科学发现通常不是那些诱人的独立试验，而是那些将知识组织成理论的试验。化学品产业的腾飞发生在在门捷列夫宣布化学元素周期表后的十年以内；詹姆士.克拉克.麦克斯韦实现电磁数字化统一后出现了无线电通讯；巴斯特和科赫的病毒理论出现后就诞生了抗生学。

With luck, something similar will soon happen in biology in the wake of such things as the Human Genome Project. In retrospect, the discovery of stem cells-cancer stem cells included-may come to be seen as a step in a comprehensive theory of how organisms work. That understanding would be a formidable, if unforeseen, part of the legacy of the war on cancer and an essential part of its mission to save lives.
如果足够运气的话，那么伴随着人类基因组计划，类似的事情将会发生在生物学界。回顾历史，包括癌症干细胞在内的干细胞发现将成为生物体运作全面理论中的重要一步。上述理解构成了抗癌战争中的重要部分，以及挽救生命任务的重要根基。

译者： Tidehunter    http://www.ecocn.org/forum/viewthread.php?tid=13996&extra=page%3D1