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  3. Cancer is a tale of two sets of genetic code, your own and your tumor’s—and tracing the unique areas of damage makes for a way t

Cancer is a tale of two sets of genetic code, your own and your tumor’s—and tracing the unique areas of damage makes for a way t

admin2014-04-20  34
问题     Cancer is a tale of two sets of genetic code, your own and your tumor’s—and tracing the unique areas of damage makes for a way to target treatment.
    Fifty years after the discovery of the first direct genetic link to cancer, scientists are assessing the state of so-called targeted therapy—with nearly 30 treatments on the market and a dozen or so more under study. " We’re still not using the ’ C ’word, ’ cure,’ " cautioned medicine director Jeff Boyd of Fox Chase Cancer Center, who helped organized a meeting to examine the future of targeted therapy. But, he added, "there is real potential to transform many cancers into chronic diseases. "
    One challenge is how to expand the number of targets to attack, in part by answering what the new chief of the National Cancer Institute calls the "big questions" about what makes this disease so intractable. What makes a tumor metastasize or spread through the body? Why some tumors spread and others don’t? What programs those tumor cells to invade, say, the liver instead of the bone or the lung? These are factors that undoubtedly could be new treatment targets.
    A domino effect of genetic alterations is required to cause any of the 200 diseases collectively called cancer. Some occur in the person, making them more prone to illness. But tumors also have their own genetic signature—four to seven genetic changes that are critical to turning, say, a normal breast or colon or liver cell into a cancerous one, and a pattern of activity that signals how aggressive that malignancy will be. Those unique patterns also offer targets for treatment, drugs that zero in on the particular genetic pathways fueling the person’s cancer—and even vaccine-like therapies, a fledgling field that aims to train patients’ immune systems to recognize and fight their tumors.
    As the targeted therapies work differently—shrinking a tumor or slowing its growth—than the tumor-destroying approaches of chemotherapy and radiation, it’s harder to prove a benefit. But Allison Frey, whose aggressive form of thyroid cancer spread to her liver in inoperable patches, says that approach has made her cancer an illness she can manage much like a diabetic manages insulin. For nearly five years, she has swallowed an experimental pill that shrank those patches and kept them from growing back, working through a pathway that targets a tumor’s blood supply. "Honestly, to me it’s just like any other chronic illness," said Frey, who’s part of a study at Fox Chase. "I show up for work every day and live life...with minimal issues. "  
The phrase "zero in"(Line 5, Paragraph 4)most probably means______.
选项 A、take aim
B、return to zero
C、pass through
D、get involved
答案A
解析 语义题。仅仅分析该词组所在分句很难准确得出答案，需将范围扩大至之前的分句Those uniquepatterns also offer targets for treatment…，意为“这个独特的结构为治疗提供了目标”，其中targets为关键词。顺承该句语义，drugs that zero in on the particular genetic pathways fueling the person’s cancer所表达的意思是“药物针对为肿瘤提供养分的遗传途径”，词组zero in应表达“对准目标”之意，故选项[A]正确。zero in虽有“归零”的意思，但与此处的文意不符，排除[B]项return to zero，考生要特别注意语义题中的这种“原词陷阱”。[C]项pass through“通过”利用后文单词pathways对考生造成迷惑，但与句意不符，较易排除。而[D]项get involved表示“介入”，虽意义接近，但不能表达“准确针对”之意，与前文的targets不能呼应，故也可排除。
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