Practice 2　　Talk about fanciful thinking. One might as well ask if there will be a war that will end all wars, or a pill that will make us all good-looking. It is also a perfectly understandable question, given that half a million Americans will die this year of a disorder that is often discussed in terms that make it seem less like a disease than an unconquerable enemy.　　What tuberculosis was to the 19th century, cancer is to the 20th: an malevolent force that frightens people beyond all reason far more than, say, diabetes or high blood pressure. The welcome boom in cancer drugs owes its beginning to one of the 20th century’s greatest scientific insights: that cancer is caused not by depression or deteriorating environment or sexual repression, but by faulty genes. Every tumor begins with just one errant cell that has been unlucky enough to suffer at least two, but sometimes several, genetic mutations. Those mutations cause the cell to replicate wildly, allowing it to escape the control that genes normally maintain over the growth of new tissue. This realization has transformed cancer, in little more than a decade, from an utterly mysterious disease into a disorder whose molecular machinery is largely understood. This new view has sparked innovations that will manage the process and keep it from killing large numbers of people.

发布日期：2022-07-10

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