What is leukemia? - Danilo Allegra and Dania Puggioni

譯者: 柏愷 邱 審譯者: Max Chern

Despite advances in medicine,

儘管醫學在進步

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

癌症仍是病患最怕聽到的診斷之一

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

之所以難以治癒的原因是 它不是一種疾病而已

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

而是可發生在不同的細胞， 超過100種疾病的群組

And one type of cancer has the unfortunate distinction

其中有一種癌症對兒童的折磨

of afflicting children more than any other type.

比其他任何一種癌症都更加難熬

This is leukemia,

那就是白血病

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

是一種始於骨髓幹細胞的癌症

A stem cell is a bit like an infant,

幹細胞有點像一個嬰兒

undeveloped but possessing great potential.

還未充分發育，但潛能無限

Many stem cells specialize and become cells of organs,

許多幹細胞能分化成特定的器官

like the liver, brain and heart.

例如肝臟，大腦和心臟

But in some tissues,

但在一些組織

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

於整個發育過程， 它們會持續分裂成新的幹細胞

and into adulthood in order to frequently generate new cells

分化成熟後，可再製造新的細胞

and keep up with the body's needs.

以應付身體的需求

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.

此處的幹細胞分化為多種血液細胞

That includes red blood cells,

包括紅血球

which carry oxygen from the lungs to all tissues,

能將氧氣從肺輸送到所有組織

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

血小板：能黏附在受傷的血管以止血

and white blood cells,

以及白血球

which patrol the body, destroying potentially harmful invaders.

負責守護身體摧毀潛在的有害入侵者

Every once in a while,

有時

something goes wrong during a stem cell's specialization process

幹細胞在特化過程中會出錯

and harmful mutations occur in the cell's DNA.

即細胞中的DNA 發生有害的突變

Cells with compromised DNA are supposed to self-destruct,

DNA突變的細胞理應自毀

but some damaged cells ignore this order,

但有些受損細胞沒有遵守這個規律

replicating uncontrollably, even as they lose their original function.

即使已喪失原有的功能 它們仍失控地不斷複製

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 為什麼白血病是兒童最常見的癌症

but one contributing factor may be

但原因之一可能是

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

白血病常常是因為 一或兩個DNA變異而導致

while most cancers require many of them,

而其他癌症則需要許多DNA變異

allowing leukemias to arise faster than other types of cancer.

因而白血病比其他癌症發病更快

Moreover, some DNA alterations can occur in white blood cells

再者，胎兒發育期間

during fetal development,

有些白血球內的 DNA 可能發生改變

further increasing the risk of early leukemia.

增加了早期罹患白血病的風險

But though it affects more children than any other cancer,

雖然白血病比其他癌症 更容易侵犯兒童

adults constitute the majority of leukemia patients overall.

但整體上，白血病仍以成人居多

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

一旦發病，受損細胞會在 血液和骨髓裡不斷複製

until they take up all available space and resources.

直到他們佔據所有空間及資源

When the bone marrow can no longer produce

當骨髓不能再產生

the required amount of functional cells,

足夠量的功能性細胞時

the blood becomes depleted.

血液變枯竭了

The lack of red blood cells

缺乏紅血球

means that muscles don't get enough oxygen,

意味著肌肉得不到足夠的氧氣

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

血小板數量減少使得傷口難以修復

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

缺乏有功能的白血球 降低了免疫功能

increasing the risk of infections.

增加了感染的風險

To restore the normal function of the blood,

要恢復血液正常功能

leukemic cells have to be eliminated.

白血病細胞必須清除

But because leukemias are not solid tumors,

但因為白血病不是實體腫瘤

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

而是利用其他方法在體內殺死癌細胞

that include chemotherapy,

包括化療

a combination of drugs that destroys quickly multiplying cells.

是一種組合數種藥物 殺死快速複製的癌細胞

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

遺憾的是這種療法 有殺死健康細胞的副作用

such as those found in hair follicles or intestines.

例如毛囊或腸道

And in some cases, the dosage required is so high

有些情況化療需要的藥量很大

that it kills all cells in the bone marrow,

會殺死骨髓裡全部的細胞

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.

一旦發生，身體便無法 自己產生新的血液細胞

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

幸運的是有外部的幫忙

from the bone marrow of a donor.

也就是來自捐贈者的骨髓幹細胞

Once transplanted into the patient,

當幹細胞被移植到患者身體內

they rapidly repopulate the bone marrow and the blood.

骨髓和血中的血液細胞便會迅速增加

However, bone marrow transplants are a complicated process

然而，骨髓移植的過程很複雜

requiring antigen compatibility between the donor and recipient

捐贈者和患者間的抗原必須相容

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

這樣才能避免植入的細胞

as foreign bodies.

將病人自己的細胞視為異物 而加以攻擊

Unlike with blood transplants,

與輸血不同的是

there are thousands of HLA types,

HLA(人類白細胞抗原)有幾千種

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

甚至兄弟姊妹與近親的HLA都不一定能相容

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

這種狀況下，搜尋範圍就要擴大到

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

包含數百萬骨髓捐贈者的基因資料庫

The more potential donors there are,

骨髓捐贈者越多

the more patients lives can be saved through successful transplants.

透過徹成功的骨髓移植 被救治的患者就越多

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

白血病雖然可怕， 但無窮的力量與希望仍在。