听力文摘：乱跑的细胞

A major reason why many cancers are so dangerous is that they metastasize. This means that instead of staying in one place, the cancer cells migrate from their original site to other parts of the body. No wonder that scientists are busy studying the mechanism¹ that enables cells to move around, in hope of finding a way to control this migration².

癌症的危险因素主要在于癌细胞转移。换而言之，癌细胞不会老实地待着，可以从原发部位转移到身体其他部位。科学家苦心研究转移细胞的原理，希望能抑制癌细胞“迁移”。

Whether it’s an immune cell going off to battle infection, or a cancer cell making its way to a new area of the body, the underlying³ mechanism for its movement is the same. All non-blood cells are surrounded by a fibrous material known as the extracellularmatrix. Anyway, cells on the go use a point-to-point adhesion system, which functions like tiny hooks, to grab the materials that make up the extracellularmatrix.

无论是“冲锋陷阵”抵御感染的免疫细胞，还是在“迁移”的癌细胞，它们运动的基本原理是相同的。除了血细胞，其他细胞均由纤维物质细胞外基质包围。移动的细胞采用点对点附着体系，就像小钩一样捕捉构成细胞外基质的物质。

So, basically, in order to move, a cell climbs hand-over-hand along the extracellularmatrix until it reaches a blood or lymphaticvessel and penetrates⁵ it. From there, it’s smooth sailing. By the way, the thinner walls of lymphaticvessels are easier to penetrate⁴, which is why examining lymph nodes plays a major role in cancer detection.

基本而言，细胞顺着细胞外基质移动，一旦发现血管或淋巴管，穿透血管和淋巴管，这样就畅通无阻了。因为淋巴管壁很薄，极易穿透，所以通过淋巴的检查可以诊断癌症。

The trick then, is not only to figure out all the factors that affect the chemical reactions that enable cells to move around, but also to figure out how to control these reactions selectively. Because cell movement is necessary for healing wounds and fighting off diseases, stopping it completely isn’t an option. Instead, scientists will have to figure out how to block movement in select locations, like in the extra-cellular matrix around growing tumors.

而关键不仅仅是找出所有因素影响细胞自由运动的化学反应，还要明白如何能有选择地控制化学反应。因为细胞运动对于伤口愈合和抵抗疾病都至关重要，完全抑制细胞运动并不可取。科学家必须解决如何抑制某些部位的运动，比如恶化的肿瘤周围的细胞外基质。

1 mechanism   

n.机械装置；机构，结构

参考例句：

• The bones and muscles are parts of the mechanism of the body.骨骼和肌肉是人体的组成部件。
• The mechanism of the machine is very complicated.这台机器的结构是非常复杂的。

2 migration   

n.迁移，移居，（鸟类等的）迁徙

参考例句：

• Swallows begin their migration south in autumn.燕子在秋季开始向南方迁移。
• He described the vernal migration of birds in detail.他详细地描述了鸟的春季移居。

3 underlying   

adj.在下面的，含蓄的，潜在的

参考例句：

• The underlying theme of the novel is very serious.小说隐含的主题是十分严肃的。
• This word has its underlying meaning.这个单词有它潜在的含义。

4 penetrate   

v.透(渗)入；刺入，刺穿；洞察，了解

参考例句：

• Western ideas penetrate slowly through the East.西方观念逐渐传入东方。
• The sunshine could not penetrate where the trees were thickest.阳光不能透入树木最浓密的地方。

5 penetrates   

v.穿过( penetrate的第三人称单数 )；刺入；了解；渗透

参考例句：

• This is a telescope that penetrates to the remote parts of the universe. 这是一架能看到宇宙中遥远地方的望远镜。 来自《简明英汉词典》
• The dust is so fine that it easily penetrates all the buildings. 尘土极细，能极轻易地钻入一切建筑物。 来自辞典例句