人類離贏得"癌症戰爭"勝利的距離(4)

These signatures represent small chemical changes to the DNA in cancers including lung, skin and ovarian cancer. Andrew Biankin, a surgeon at the University of Glasgow in the UK, was one of the researchers involved. He says it was possible to observe the "insult to the DNA" that left a tell-tale sign of the damage.

這些生物標示顯示了在肺癌，皮膚癌，卵巢癌等癌症中基因上的小的化學變化。在格拉斯哥大學任職的外科專家安德魯.比安金（Andrew Biankin）是研究小組成員之一。他認爲通過觀察可以發現每個受攻擊的基因留下的受損的標記。

In skin cancer like melanoma, we can see evidence of UV light exposure, in lung cancer can see a particular signature of smoking exposure, explains Biankin. "We can see evidence of there being an inherited inability to repair DNA."

“通過觀察，我們發現皮膚癌中的惡性黑色素瘤中有明確的證據顯示與紫外線暴曬有直接關係，而在肺癌中能夠發現由於吸菸所導致的印記,”安德魯教授進一步解釋。“而證據顯示這些受損的基因細胞通過遺傳也永遠無法得到修復。”

As well as these known cancer signatures, the team could see unusual cancer-forming patterns where the cause was unclear. "There's [now] a lot of effort in trying to work out what these causes are," he says.

“除了已知的癌症標識，研究小組還發現了不同尋常的癌細胞基因組成結構，但並不清楚癌症的誘因是什麼，我們的團隊正在努力尋找出原因，”他說。

The core challenge for researchers like Biankin and Cancer Research UK, who funded the study, will be to understand exactly what leads to these types of genetic change.

”對於比安金和贊助這個項目的英國癌症研究的科學人員來說，最大的挑戰來自於必須要非常清晰的理解尋找出基因變異的原因。

While it is vital to understand the causes of cancer and to find new treatments, others stress that for now it is more important to focus on prevention. That is because there are known risk factors that contribute to cancer-causing mutations, such as smoking and sunburn.

尋找針對癌症的有效治療辦法，理解癌症誘因至關重要，另外一些人則強調目前更重要的是癌症的預防。因爲現在清晰的證據表明，一些潛在風險能夠導致基因突變引發癌症，例如吸菸及陽光下的暴曬。

Otis Brawley, chief medical officer at the American Cancer Society, says focusing on some of these risks could prevent many instances of cancer forming in the first place. He cites two startling statistics: in 1900 the age-adjusted death rate for cancer in the US was 65 per 100,000, but this had jumped to 210 deaths per 100,000 only 90 years later.

美國癌症社會(American Cancer Society)的首席醫療官奧蒂斯.布勞利（Otis Brawley）認爲專注於這些潛在風險能夠預防癌症的形成。他給出了兩個驚人的數字，在1900年美國每10萬人當中有65個人因患癌症死亡，但是僅僅在90年後，在同規模的調查中，因患癌症死亡人數迅速飆升至210人。

If you have something that has increased that quickly over 90 years, there's something that causing it, says Brawley. "If you can remove the cause you can decrease the cancer."

“這說明在過去90年中有一些因素導致了癌症發病率的提高。如果我們能夠消除誘因，那麼患癌率將會下降。”

In the US there has been a 25% decline in death rate in the last two decades. "More than half of that decline is driven by cancer prevention activities," says Brawley.

美國在過去20年中死亡率下降了25%，“有超過一半的原因是因爲癌症預防活動的普及，” 布勞利說。

This points to the fact that some of the cancers that would previously have killed people had been prevented. Almost a third of death from cancer in the US has been attributed to cigarette smoking, for example. This makes tobacco "the single most preventable cause of death in the world", according to Cancer Research UK.

這說明一些曾經導致死亡的癌症病因得到了有效的預防。例如，在美國，吸菸導致了超過三分之一的癌症死亡. 根據英國癌症研究機構的說法吸菸就是“世界上最能夠通過預防而避免的死因。”

Although it is obviously good that death rates are falling, overall cancer diagnoses are on the rise.

儘管癌症死亡率下降是個好消息，患癌率卻在逐年上升。

There is a degree to which this is because certain cancers are now better diagnosed, and so cases are more likely to be identified and counted. This is true of prostate cancer, for instance.

從某種程度上說這是因爲某些癌症並不太容易診斷，因此病例也沒有被發現和統計。比如前列腺癌就屬於這種情況。

But a more telling reason for the rise is that humans, on average, live a lot longer than they used to. "If you live long enough you will get cancer," says Biankin.

但另一個更爲顯而易見的原因就是人類的平均壽命比以前要長得多。所以“如果你活的時間足夠長，你就有可能會得癌症，”比安金如是說。

If we decide that we all want to live to more than 70, then we have to accept that sooner or later we will get some sort of cancer, says Bardelli. It is inevitable because our cells have not evolved to maintain their DNA for as long as we now live, he says.

“如果我們決定我們都要活過70歲，那麼我們就需要接受一個現實，早晚我們都會患癌症。”巴爾代利說到。因爲在如此長的進化過程中，我們的細胞無法一直持續的維持我們的基因穩定的進化。

Brawley goes even further, and says that everyone over 40 will get a mutation that can cause cancer at some point. That sounds alarming, but fortunately our natural defence mechanisms will usually stop the mutation in its tracks by destroying the mutant cell before it can grow into a full-blown tumour.

布勞利教授的觀點可能更嚇人，根據他的理論，任何人只要超過40歲，體內的細胞就有可能發生變異。只不過我們有着完善的自我防禦系統，能夠迅速識別這些變異的細胞，並且在他們還沒有真正成爲癌細胞的時候就被身體的防衛機制摧毀。

Even though the rise in cancer is an almost inevitable consequence of other improvements in our health, progress towards better treatments is continuing apace.

人類健康狀況的提升帶來一個無法避免的結果就是癌症病例也在上升，而找到更有效的治療方法也在不斷的進步。

And peering back into how life works to "fight evolution with evolution" may well provide further breakthroughs. "Our host, our body has to make use of resources that have been growing for millions and millions of years," says Bardelli.

回顧生命如何“用進化打敗進化”可能會提供更多的突破口。“我們的宿主，我們的身體應該充分利用發展了上百萬年的資源，”巴爾代利說到。

There is hope. I have no doubt we will beat cancer, no doubt, he says. "Sometimes we fail because we don't identify the problem as it should be. It's nobody's fault, it's how science works."

“未來充滿希望。毫無疑問我們最終將戰勝癌症，我毫不懷疑這一點。有些時候我們失敗了是因爲我們並沒有明確問題所在，這不是任何人的錯誤，科學就是這樣運作的，”他說。