cancer remains one of the most frightening diagnoses patients can receive.

癌症依然是病患最害怕被診斷出來的病症之一。

What makes it so difficult to cure is that it's not one illness,

會這麼難以治療的原因，是因為癌症不只包含一種疾病，

but a family of over 100 diseases occurring in different types of cells.

而是超過100種病症出現在不同的細胞裡。

And one type of cancer has the unfortunate distinction

有一種癌症，相較於其他種類的疾病，

of afflicting children more than any other type.

更讓幼小孩童感到折磨、痛苦。

This is leukemia,

這就是所謂的白血病。

a cancer that begins in stem cells found in the bone marrow.

這種癌症發源於骨髓中的幹細胞。

A stem cell is a bit like an infant,

幹細胞有如嬰兒一般，

undeveloped but possessing great potential.

未被開發但擁有強大的潛力。

Many stem cells specialize and become cells of organs,

許多幹細胞專化成為器官的細胞，

like the liver, brain and heart.

例如肺臟、大腦以及心臟。

But in some tissues,

但在一些組織中，

they can continue to divide into new stem cells throughout development,

他們可以在整個發展過程中持續分裂成新的幹細胞，

and into adulthood in order to frequently generate new cells

並且進入成長期，為了頻繁生殖新的細胞，

and keep up with the body's needs.

以及維持身體所需。

One example is the bone marrow,

其中一個例子就是骨髓，

where stem cells differentiate into many types of blood cells.

幹細胞分化成不同種類血球的地方。

That includes red blood cells,

包含了紅血球，

which carry oxygen from the lungs to all tissues,

從肺部運送氧氣到各個身體組織。

platelets, which help stop bleeding by sticking to damaged blood vessels,

血小板，透過黏合受損血管的地方來止血。

and white blood cells,

另一個是白血球，

which patrol the body, destroying potentially harmful invaders.

到處在體內巡邏，消滅潛在的有害侵入者。

Every once in a while,

每過一段時間，

something goes wrong during a stem cell's specialization process

幹細胞特化過程出現問題，

and harmful mutations occur in the cell's DNA.

細胞中的DNA發生有害的突變。

Cells with compromised DNA are supposed to self-destruct,

DNA受到危急的細胞照常理會自我毀滅，

but some damaged cells ignore this order,

但一些受損的細胞跳過這個程序，

replicating uncontrollably, even as they lose their original function.

不受控制的複製，即便已經沒有原先的機能。

These are what we know as cancer cells.

這就是我們所謂的癌細胞。

It is not yet clear why leukemia is the most common childhood cancer,

我們還不清楚為什麼白血病多發生在孩童身上，

but one contributing factor may be

但其中一個可能因素是

that leukemias are often caused by just one or two DNA modifications,

通常一兩個DNA變異便會造成白血病，

while most cancers require many of them,

而其他癌症則需要更多的DNA變異，

allowing leukemias to arise faster than other types of cancer.

相較於其他癌症，這使白血病擴散更迅速。

Moreover, some DNA alterations can occur in white blood cells

此外，白血球中的DNA變異

during fetal development,

最早有可能發生在胚胎生長時期，

further increasing the risk of early leukemia.

這更增加早期罹患白血病的風險。

But though it affects more children than any other cancer,

雖然白血病比起其他癌症對孩童的影響更多，

adults constitute the majority of leukemia patients overall.

成人罹患白血病依舊是占大多數。

Once leukemia strikes, the damaged cells reproduce in the blood and the bone marrow

一旦病發，受損的細胞在血液及骨髓中繁殖，

until they take up all available space and resources.

並且佔領所有空間和資源。

When the bone marrow can no longer produce

當骨髓無法製造

the required amount of functional cells,

人體所需的機能細胞，

the blood becomes depleted.

血液開始衰竭。

The lack of red blood cells

缺少紅血球，

means that muscles don't get enough oxygen,

表示肌肉無法獲得充足的氧氣，

the reduced number of platelets is not sufficient to repair wounds,

血小板數量銳減將無法有效修復傷口，

and the dearth of functional white blood cells impairs the immune system,

功能性白血球的減少，削弱了免疫系統，

increasing the risk of infections.

增加感染的風險。

To restore the normal function of the blood,

為了儲存正常機能的血液，

leukemic cells have to be eliminated.

白血病的細胞必須被消滅。

But because leukemias are not solid tumors,

但是白血病不是腫瘤，

they can't be removed surgically.

無法透過手術移除，

Instead, the cells are killed inside the body using various treatments

藉由使用不同的治療方式代替，讓身體內的細胞被消滅，

that include chemotherapy,

其中包含了化療，

a combination of drugs that destroys quickly multiplying cells.

使用不同種類的藥物迅速銷毀細胞繁殖的方式。

Unfortunately, this has the side effect of killing healthy cells,

不幸的是，其副作用為健康細胞也無一倖免，

such as those found in hair follicles or intestines.

例如頭髮毛囊或小腸。

And in some cases, the dosage required is so high

在某些情況，需要高劑量

that it kills all cells in the bone marrow,

殺死骨髓中的細胞，

including stem cells.

包括幹細胞。

When this happens, the body is no longer able to create new blood cells on its own.

在此情況下，身體不再能自行製造新的血球。

Fortunately, outside help can come in the form of stem cells

好消息是，身體可以接受

from the bone marrow of a donor.

捐贈者骨髓中的幹細胞。

Once transplanted into the patient,

一旦移植到病患體內，

they rapidly repopulate the bone marrow and the blood.

幹細胞迅速重新注入骨髓和血液。

However, bone marrow transplants are a complicated process

然而，骨髓移植是個複雜的過程，

requiring antigen compatibility between the donor and recipient

捐贈者和接受者雙方的抗原必須要一致，

to keep the transplanted cells from attacking the patient's own cells

為了讓移植的細胞不會被患者自身的細胞

as foreign bodies.

視為外來物而攻擊，

Unlike with blood transplants,

和血液輸送不一樣。

there are thousands of HLA types,

人類白細胞抗原(HLA)有上千種，

and even siblings and close relatives may not have compatible bone marrow.

即便是兄弟姐妹或近親也無法有相同的骨髓。

If this is the case, the search is expanded to a database

如果此事發生了，搜尋便擴大至整個資料庫，

containing the genetic makeup of millions of voluntary bone marrow donors.

包含數以千萬自願骨髓捐贈者的基因配對。

The more potential donors there are,

越多潛在的捐贈者，

the more patients lives can be saved through successful transplants.

越多患者可以透過移植而成功存活下來。

Leukemia may be a frightening disease, but there is strength and hope in numbers.

白血病雖然可怕，但背後依然有許多人給予力量和希望支持著。