to push the drug out, before the drug can have any effect. 把药物推开，药物根本来不及起任何作用。

Imagine -- the cell effectively spits out the drug. 就好比细胞一口把药吐出去。

This is just one example of the many genetic tricks in the bag of our supervillain, cancer. 而这仅仅是我们的大反派--癌症的众多基因把戏之一。

All due to mutant genes. So, we have a supervillain with incredible superpowers. 这一切都跟突变基因有关。因此，我们要面对的是拥有超强能力的大反派。

And we need a new and powerful mode of attack. Actually, we can turn off a gene. 我们需要新的、更强大的攻击方式。实际上，我们可以关闭基因。

The key is a set of molecules known as siRNA. 开关是一系列叫siRNA的分子（即小分子干扰核糖核酸）。

siRNA are short sequences of genetic code that guide a cell to block a certain gene. 它是一小段基因编码，可以让细胞阻止某些特定基因（发挥作用）。

Each siRNA molecule can turn off a specific gene inside the cell. 每一个siRNA都能关闭细胞内部某个特定的基因。

For many years since its discovery, scientists have been very excited about how we can apply these gene blockers in medicine. 自siRNA被发现后，科学家们兴奋了好多年，因为他们可以将这种基因拦截者加入药物中。

But, there is a problem. siRNA works well inside the cell. 但是，有一个问题。siRNA在细胞内部可以正常发挥作用。

But if it gets exposed to the enzymes that reside in our bloodstream or our tissues, it degrades within seconds. 但如果它接触到位于我们血液或者组织中的酶的话，几秒钟内就会被降解。

It has to be packaged, protected through its journey through the body on its way to the final target inside the cancer cell. 因此，它们必须被包裹及保护起来，才能完成在人身体里的旅程，顺利抵达最终目标--癌细胞内部。