We've harnessed electricity,

我們已經學會使用電力

sequenced the human genome,

排列人類基因序列

and eradicated small pox.

也有了能根除瘟疫的技術

But after billions of dollars in research,

但即使已經投入幾十億的資金研究

we haven't found a solution for a disease that affects more than 14 million people

對於這個影響全球超過一千四百萬人口的疾病

and their families at any given time.

我們仍未找到治療方法

Cancer arises as normal cells accumulate mutations.

隨著正常細胞產生變異，癌症發作機率提高

Most of the time, cells can detect mutations or DNA damage

大多時候，細胞能偵測到突變或是 DNA 受損

and either fix them or self destruct.

並且進行修復或是自我摧毀

However, some mutations allow cancerous cells to grow unchecked

然而，有些突變使得癌化細胞不容偵測

and invade nearby tissues,

甚至使之有機會感染周圍組織

or even metastasize to distant organs.

或是轉移到臨近器官

Cancers become almost incurable once they metastasize.

一旦經過轉移，癌症就幾乎是無可醫治

And cancer is incredibly complex.

再者，癌症極其複雜

It's not just one disease.

它並非是一種單一疾病

There are more than 100 different types

總計有一百種以上的癌症

and we don't have a magic bullet that can cure all of them.

我們卻沒有一個方法能治好所有癌症

For most cancers,

大多數癌症的治療方法

treatments usually include a combination of surgery to remove tumors

通常包括動手術移除腫瘤

and radiation and chemotherapy to kill any cancerous cells left behind.

再透過放射線和化療殺除剩餘的癌細胞

Hormone therapies,

其他方法如荷爾蒙療法、

immunotherapy,

免疫療法、

and targeted treatments tailored for a specific type of cancer

和針對特定癌症所設計的標靶療法

are sometimes used, too.

有時也會被採用

In many cases, these treatments are effective

在許多案例中，這些療法成功見效

and the patient becomes cancer-free.

使病患脫離癌症

But they're very far from 100% effective 100% of the time.

但還算不上是每次都有效，效力也並非百分之百

So what would we have to do to find cures for all the different forms of cancer?

所以，我們該如何找到能治療所有癌症的療法呢？

We're beginning to understand a few of the problems

我們漸漸意識到幾個科學家

scientists would have to solve.

必須解決的問題

First of all, we need new, better ways of studying cancer.

首先，我們需要一個更好、更先進的方式來研究癌症

Most cancer treatments are developed using cell lines grown in labs

多數癌症療法起源自從人類腫瘤取下的癌細胞株

from cultures of human tumors.

在實驗室培植出的結果

These cultured cells have given us critical insights

這些培植的細胞給了我們很好的管道

about cancer genetics and biology,

好了解細胞遺傳學和生物學

but they lack much of the complexity of a tumor in an actual living organism.

但是和真實活著的生物體以內的腫瘤一比，它們就少了許多複雜性

It's frequently the case that new drugs, which work on these lab-grown cells,

常有的是，新藥能作用在實驗室培養出的細胞

will fail in clinical trials with real patients.

卻在人體測試階段時失去效用

One of the complexities of aggressive tumors

惡性腫瘤的複雜性在於

is that they can have multiple populations of slightly different cancerous cells.

它能分裂出許多有些微差異的癌細胞群

Over time, distinct genetic mutations accumulate in cells

隨著時間，相異的基因突變在腫瘤不同部位的細胞裡堆積

in different parts of the tumor, giving rise to unique subclones.

使得獨特形態的亞克隆得以產生

For example, aggressive brain tumors called glioblastomas

舉例來說，一種稱為「多形性膠質母細胞瘤」的腦部惡性腫瘤

can have as many as six different subclones in a single patient.

能夠在一個病患體內產生多達六種不同的亞克隆

This is called clonal heterogeneity,

這叫做克隆異質性

and it makes treatment difficult because a drug that works on one subclone

這也使得治療更加困難，因為一種藥劑對這個亞克隆有用

may have no effect on another.

不見得對另一個亞克隆也一樣有用

Here's another challenge.

還有另一個困難點

A tumor is a dynamic interconnected ecosystem

腫瘤是一種動態的、有內部網絡的生態系統

where cancer cells constantly communicate with each other

癌細胞因而隨時在與彼此連結

and with healthy cells nearby.

也包括和周圍健康細胞交流

They can induce normal cells to form blood vessels that feed the tumor

他們能哄騙正常細胞組織血管替腫瘤提供養分

and remove waste products.

和排出廢物

They can also interact with the immune system

他們也能和免疫系統交流

to actually suppress its function,

抑制免疫作用

keeping it from recognizing or destroying the cancer.

讓癌細胞不被免疫系統偵測並摧毀

If we could learn how to shut down these lines of communication,

如果我們學會把這些交流網絡斬斷

we'd have a better shot at vanquishing a tumor permanently.

就更有可能成功根除腫瘤

Additionally, mounting evidence suggests

再者，大量證據顯示

we'll need to figure out how to eradicate cancer stem cells.

我們必須搞懂如何撲滅癌細胞的幹細胞

These are rare but seem to have special properties

他們很罕見但卻有特殊能力使自己

that make them resistant to chemotherapy and radiation.

對化療和放射線免疫

In theory, even if the rest of the tumor shrinks beyond detection during treatment,

理論上，即使在治療過程腫瘤的大部分都已經縮小到無法偵測的範圍

a single residual cancer stem cell could seed the growth of a new tumor.

哪怕只有一點殘存的癌幹細胞，腫瘤終能捲土重來

Figuring out how to target these stubborn cells

找到方法對付這些頑強細胞

might help prevent cancers from coming back.

或許就能防止癌症復發

Even if we solved those problems, we might face new ones.

即使我們解決了這些問題，我們還是可能面臨新問題

Cancer cells are masters of adaptation,

癌細胞非常善於適應環境

adjusting their molecular and cellular characteristics to survive under stress.

在遭受放射線和化療攻擊的情況下

When they're bombarded by radiation or chemotherapy,

他們能改變分子和細胞結構

some cancer cells can effectively switch on protective shields

有些癌細胞甚至能在受到威脅時

against whatever's attacking them by changing their gene expression.

及時改變基因形成防護膜

Malignant cancers are complex systems that constantly evolve and adapt.

惡性癌症系統複雜，且隨時在變化、適應

To defeat them, we need to find experimental systems

要想擊潰他們，我們必須找到一個適合的實驗系統

that match their complexity,

能夠符合他們的複雜生態

and monitoring and treatment options that can adjust as the cancer changes.

並且隨時監控癌細胞變化使治療方針得以及時應變

But the good news is we're making progress.

好消息是我們一直在進步

Even with all we don't know,

雖然目前我們仍有不足

the average mortality rate for most kinds of cancer

自從一九七零年代以來的大多數癌症平均致死率

has dropped significantly since the 1970s and is still falling.

已經大幅度降低，未來也將持續下去

We're learning more every day,

我們每天都學到了更多

and each new piece of information gives us one more tool to add to our arsenal.

每一項新資訊也將使我們有更多的武器對付癌症