前列腺癌的7大遗传风险因子

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7 genetic risk factors found for prostate cancer
Discoveries shed light on disease particularly pervasive among black men

Updated: 2:35 p.m. ET April 1, 2007
WASHINGTON - Scientists have identified several genetic risk factors for prostate cancer, shedding new light on the cause of a leading worldwide cancer killer among men that hits U.S. blacks especially hard.

“The importance of it is that this is the first real evidence of the genetic basis of prostate cancer,” said Dr. Brian Henderson, dean of the Keck School of Medicine at the University of Southern California and one of the researchers of the study released on Sunday.

“It gives us the first real insight we’ve had into the cause of this disease and how we might do something about it,” Henderson added.

The researchers described seven genetic risk factors — DNA sequences present in some people but not others — bunched in a relatively small region of one of the human chromosomes, chromosome 8, that reliably predicted one’s probability of developing prostate cancer.

Five were newly discovered and two confirmed earlier findings.

The prostate, about the size of a walnut, is a gland below a man’s bladder that produces fluid for semen. According to the American Cancer Society, prostate cancer is the second leading cause of cancer deaths in men, behind lung cancer.

Pinpointing these genetic risk factors could be an important step toward helping explain the higher prevalence in U.S. blacks compared to whites, the researchers said.

Black men are twice as likely to die of the disease, and nearly all of the risk factors were seen most frequently in blacks involved in the study.

Henderson said the disease’s greater prevalence among blacks had hinted at some sort of a genetic basis for it.

The findings also could lead to ways to sort out who is at highest risk by finding if a man has one of the genetic risk factors, and for early diagnosis of the disease, the researchers said.

Prostate cancer death rates are falling in part because screening is allowing it to be found earlier when it is more treatable.

‘It's not all genetic’
“We do believe there is a genetic basis. Of course, it’s not all genetic. There are also going to be other lifestyle and environmental factors as well,” said Christopher Haiman, a USC preventive medicine professor.

“But our findings here in this study suggest that a large fraction of the disparity between African Americans and other populations could be due to genetic variation in this region,” Haiman said.

About two-thirds of cases are in men over age 65. The American Cancer Society said men who eat a lot of red meat or high-fat dairy products appear to have higher risk.

The three teams of researchers — one led by scientists at Harvard University and USC, one by Icelandic company deCODE genetics Inc. and one by the National Cancer Institute, part of the U.S. National Institutes of Health — presented their findings in the journal Nature Genetics.

The researchers examined genetic information on thousands of men with and without prostate cancer.
前列腺癌的七大遗传风险因子

对黑人男性中广泛存在的疾病的探索使我们对疾病有了更深入的了解

据MSN4月1日新闻报道，科学家们最近发现了好几种前列腺癌的遗传风险因子，这使我们彻底了解了这种使美国黑人深受其害且在世界范围内居男性癌患首位的疾病的病因。

研究人员之一，南加州大学Keck医学院的院长Brian Henderson博士在周日说到：“这项研究的重要性在于这是我们第一次发现了前列腺癌遗传基础的真正证据。”

Henderson补充到：“这也是我们第一次洞察了这种疾病的病因，因此我们可以做一些相关的工作。”

研究者们介绍了这七个遗传风险因子――一些人所含有的特殊的DNA序列而另外的人却没有――聚集在人类8号染色体上一个相对较小的区域，而且它们能够可靠的预测一个人患前列腺癌的概率有多大。

其中的五个是最新发现的，其余两个证实了以前的发现。

只有核桃大小的前列腺是一个位于人体膀胱下面的腺体，它所制造出来的前列腺液是精液的重要成份。根据美国癌症学会的统计，前列腺癌位于肺癌之后已经成为男性第二大癌症死亡病因。

研究者们说准确的找到这些遗传风险因子是向试图解释美国黑人比白人有更高的发病率方面迈出了重要的一步。

黑人男性较之白人有两倍的危险死于这种疾病，而且在这项研究中几乎所有的风险因子在黑人中出现的频率更高。

Henderson说黑人中这种疾病的高发病率在某种程度上暗示了这种疾病应该存在遗传基础。

研究人员说通过寻找一个人是否具有遗传风险因子，这项研究结果可以衍生出为具有高危险的人进行分类的方法，从而能够对这种疾病进行早期诊断。

前列腺癌的死亡率已经下降了一部分，主要是因为筛检使这种疾病能够在早期被发现，而且治疗起来也相对容易一些。

“它并不全是遗传造成的”

南加州大学预防医学教授Christopher Haiman说：“我们的确相信它有遗传基础。但是，它并不全是遗传造成的。其它生活方式和环境因素也对这种疾病有影响。”

Haiman说：“但是这项研究的发现表明非洲裔美国人和其它人群之间的差异很大一部分是由于这个人群的基因变异造成的。”

大约2/3的前列腺癌患者都是65岁以上的老年男性。美国癌症学会说那些食用大量的红色肉类（暗红色的生肉,尤其是牛肉,羊肉,鸡腿肉）或富含脂肪的乳酪制品的人患这种疾病的危险性更高。

三组研究人员在《自然-遗传学》杂志上公布了他们的研究结果，他们分别是哈佛大学和南加州大学的科学家组成其中一组，另一组由冰岛的解码基因公司组成，最后一组由美国国立卫生研究所的一部分国立癌症研究所组成。