人教版高中英语选修6 UNIT 3 A HEALTHY LIFE PERIOD 3 素材（3） .doc

1、Gene Chip Predicts Outcome of Cancer TherapyBecause cancer patients with the same diagnosis often vary widely in their response to treatment, researchers have long suspected that they might be dealing with different types of tumors. Now a team has confirmed that hunch: A DNA-studded chip has shown t

2、hat one type of lymph system cancer can begin in two different parts of the immune system. Using that information, the investigators could predict which patients were most likely to benefit from chemotherapy. The work paves the way toward blending drug cocktails to fit a patients tumor. One particul

3、arly aggressive cancer, diffuse large B cell lymphoma (DLBCL) afflicts 25,000 people in the United States each year. As the cancer takes hold, malignant B cells and other immune cells spread throughout the blood stream and lymph organs. As only 40% of patients benefit from chemotherapy, researchers

4、suspected that DLBCL and other lymphomas could be caused by a variety of cell types gone haywire. Finding the original source might mean predicting the best drugs to wipe the cancer out, researchers hoped. To test this hypothesis, a team led by molecular biologist Louis Staudt of the National Cancer

5、 Institute (NCI) in Bethesda, Maryland, sought the origins of tumors from 40 patients with DLBCL and other forms of lymphoma. The researchers studded tiny chips with almost 18,000 different fragments of DNA-pieces of genes known to be expressed in a variety of either normal or cancerous cells. They

6、extracted genetic material from the tumors as well as normal tissue, labeled the molecules with a fluorescent dye, and passed them over the so-called Lymphochips. When the cells genetic material bumps into the matching anchored fragment on the chips, it sticks and emits a signal. Almost 2 million si

7、gnals later, researchers could separate the malignancies into two groups. One had gene expression patterns reminiscent of B cells that live in lymph organs such as the lymph nodes, spleen, or tonsils, suggesting that the metastatic cancer first arose from cells lodged in these organs. The other grou

8、p pumped out gene products that looked like those from blood-borne immune cells, the team reports in todays Nature. When the researchers checked their results against the medical records of the cancer patients, they found that the majority of the patients with lymph organ cancer cells had responded

9、to chemotherapy, while those with the blood cell form had not. It is a beautiful illustration of what technology can do, says molecular biologist Anton Berns, director of the Netherlands Cancer Institute in Amsterdam. The NCI team plans to verify their results in larger groups of patients, possibly

10、tease apart more varieties of lymphoma, and eventually make such chips available for clinical diagnoses. Meanwhile, other researchers have been fast and furiously developing their own versions of the Lymphochip to refine diagnoses of other cancers. 用基因芯片预测癌症治疗的效果有同样诊断的癌症病人对治疗的反应经常有很大的差别，因此科学家一直在怀疑他们

11、其实是在对付不同的肿瘤。现在一个研究小组证实了这一猜测：用DNA芯片他们发现一类淋巴系统的癌可能从免疫系统的两个不同的部位开始。利用这一信息，研究人员也许能预测哪些病人更有可能从化疗得到好处。这一工作为配制针对病人肿瘤的药物鸡尾酒开辟了道路。 美国每年有约2万5千人患一种名为弥散大B细胞淋巴瘤(diffuse large B cell lymphoma, 简称DLBCL)的极富侵略性的癌。癌住入病人体内后，恶性B细胞和其它免疫细胞扩散到整个血液和淋巴系统中。只有40%的病人得益于化疗，研究人员怀疑DLBCL和其它淋巴瘤可能是不同的类型的细胞出问题而形成的。他们希望通过找到出问题的细胞能够预测使

12、用哪些药物可以消除癌变。 为了检验这个设想，美国国家癌症研究所(National Cancer Institute，NCI)的分子生物学家Louis Staudt带领一个小组在40个DLBCL和其它淋巴瘤患者中寻找肿瘤的起源。他们用已知的18000多种在正常和癌变细胞中表达的DNA片段制成DNA芯片。然后从正常和癌细胞中取出基因材料，用荧光染料对它们加以标识，然后让它们经过所谓的Lymphochips。当细胞的基因物质碰上与其匹配的DNA芯片上的片段时，就会被粘住同时发出信号。 测了200万个信号之后，研究人员发现可把恶性细胞分为两类。一类的表达模式与淋巴器官(比如淋巴结、脾、扁桃体)中的B细胞有关，意味着转移性癌首先是从这些器官的细胞变化开始的。令一类基因看上去与血液中的免疫细胞有关。这个小组在2月3日的自然杂志中报告了他们的结果。但研究人员将他们的结果与癌症病人的医疗记录相比时，他们发现大多数淋巴器官细胞癌变的病人响应化疗，而血液免疫细胞癌变的病人不响应化疗。 荷兰癌症研究所所长、分子生物学家Anton Berns说，“这是一个现今技术水平的美妙的演示。”NCI小组打算用更大的患者群来证实他们的结果，也许能找出淋巴瘤的更多的类型，最终，他们将把芯片提供给临床诊断之用。同时，其他研究人员也在为进一步诊断癌症而努力开发他们自己的DNA芯片。