就最近的Angelina Jolie事件科普一下BRCA1/BRCA2# ChineseMed - 中医
W*r
1 楼
先从官方网站上抄录几段。
What is known about the BRCA1 and BRCA2 genes?
Because family history is the strongest single predictor of a woman's chance
of developing breast cancer, researchers turned to cancer-prone families -
those with a high incidence of cancer in several generations - to find
specific inherited gene alterations that are passed on from one generation
to the next. After a long search, two genes were found that are altered in
many families with hereditary breast cancer. The first, BRCA1 (for BReast
CAncer gene), was discovered in 1994, and the second, BRCA2, in 1995. The
search for other genes continues.
Within families with cancer in multiple generations, it had been estimated
previously that a woman with an alteration in the BRCA1 gene has about an 85
percent chance of developing breast cancer and a 44 percent chance of
developing ovarian cancer by age 70. Prior research in these high-risk
families reported that women with BRCA2 alterations have a lower risk of
developing both breast and ovarian cancer than women with BRCA1 alterations.
Previous studies had reported an increased risk of colon and prostate
cancer associated with alteration carriers in these same families.
Most alterations result in a shortened protein product which scientists
assume prevents the protein from carrying out its normal function in the
cell. The precise biological roles of BRCA1 and BRCA2 are not known.
Once the genes were isolated, it was possible to analyze the specific
alterations inherited in each cancer-prone family. Today over 100 different
alterations scattered throughout BRCA1 have been identified. In general,
most families have a unique alteration. A similar pattern is emerging for
BRCA2 alterations seen in cancer-prone families; a large number of distinct,
family-specific alterations are scattered through the gene.
The initial impetus for the current study was the observation in late 1994
that three high-risk Ashkenazi families studied at the NIH carried an
identical alteration in BRCA1 (185delAG). These families were not known to
be related. This observation led to the study which found that 1 percent of
the Jewish population has this alteration. This was the first alteration
associated with a particular ethnic group. A few other alterations
frequently occurring in other ethnic groups (Icelandic, Norweigan and Dutch)
have been found since then and are now being studied.
原文出处：
http://www.genome.gov/10000940#al-3
留意里面非常重要的一句话：Most alterations result in a shortened protein
product which scientists assume prevents the protein from carrying out its
normal function in the cell. The precise biological roles of BRCA1 and BRCA2
are not known. 也就是说，这只是科学家的一个假设。具体的机制是没有人知道的。
据我所知，要用实验的方法实实在在地观察到一个有缺陷的基因如何生成一个有缺陷的
蛋白质，而这个有缺陷的蛋白质又是如何在几十年的时间里诱发肿瘤，这是非常困难的
，几乎就是不可能的。所以我一直很好奇，BRCA1、BRCA2和乳癌之间的link是怎么找到
，又是怎么confirm的呢？我决定做一次彻底的研究，于是就找到了这篇文章。原来他
们使用的是统计的方法。科学家们首先找出乳癌发病率比较高的家族，然后寻找这些家
族成员的哪些基因和其他人不同。他们在1994年找到了BRCA1，在1995年找到了BRCA2。
于是他们就认为BRCA1和BRCA2的变异导致了乳癌。这个结论有多可靠呢？我看不到原始
数据，也不知道他们具体使用什么统计方法，不好下结论。但我自己是倾向于不相信。
有兴趣的朋友可以看一下我的另一个帖子
http://www.mitbbs.com/article0/ChineseMed/12638651_0.html
里面的“高尔夫球落点原理”一节，然后自己决定要不要相信。在我看来，他们所说的
携带BRCA1变异基因的人在70岁前生乳癌的概率是85%的这个数字和我在“高尔夫球落点
原理”一节里面计算出来的相关系数0.7848似乎有异曲同工之妙。
What is known about the BRCA1 and BRCA2 genes?
Because family history is the strongest single predictor of a woman's chance
of developing breast cancer, researchers turned to cancer-prone families -
those with a high incidence of cancer in several generations - to find
specific inherited gene alterations that are passed on from one generation
to the next. After a long search, two genes were found that are altered in
many families with hereditary breast cancer. The first, BRCA1 (for BReast
CAncer gene), was discovered in 1994, and the second, BRCA2, in 1995. The
search for other genes continues.
Within families with cancer in multiple generations, it had been estimated
previously that a woman with an alteration in the BRCA1 gene has about an 85
percent chance of developing breast cancer and a 44 percent chance of
developing ovarian cancer by age 70. Prior research in these high-risk
families reported that women with BRCA2 alterations have a lower risk of
developing both breast and ovarian cancer than women with BRCA1 alterations.
Previous studies had reported an increased risk of colon and prostate
cancer associated with alteration carriers in these same families.
Most alterations result in a shortened protein product which scientists
assume prevents the protein from carrying out its normal function in the
cell. The precise biological roles of BRCA1 and BRCA2 are not known.
Once the genes were isolated, it was possible to analyze the specific
alterations inherited in each cancer-prone family. Today over 100 different
alterations scattered throughout BRCA1 have been identified. In general,
most families have a unique alteration. A similar pattern is emerging for
BRCA2 alterations seen in cancer-prone families; a large number of distinct,
family-specific alterations are scattered through the gene.
The initial impetus for the current study was the observation in late 1994
that three high-risk Ashkenazi families studied at the NIH carried an
identical alteration in BRCA1 (185delAG). These families were not known to
be related. This observation led to the study which found that 1 percent of
the Jewish population has this alteration. This was the first alteration
associated with a particular ethnic group. A few other alterations
frequently occurring in other ethnic groups (Icelandic, Norweigan and Dutch)
have been found since then and are now being studied.
原文出处：
http://www.genome.gov/10000940#al-3
留意里面非常重要的一句话：Most alterations result in a shortened protein
product which scientists assume prevents the protein from carrying out its
normal function in the cell. The precise biological roles of BRCA1 and BRCA2
are not known. 也就是说，这只是科学家的一个假设。具体的机制是没有人知道的。
据我所知，要用实验的方法实实在在地观察到一个有缺陷的基因如何生成一个有缺陷的
蛋白质，而这个有缺陷的蛋白质又是如何在几十年的时间里诱发肿瘤，这是非常困难的
，几乎就是不可能的。所以我一直很好奇，BRCA1、BRCA2和乳癌之间的link是怎么找到
，又是怎么confirm的呢？我决定做一次彻底的研究，于是就找到了这篇文章。原来他
们使用的是统计的方法。科学家们首先找出乳癌发病率比较高的家族，然后寻找这些家
族成员的哪些基因和其他人不同。他们在1994年找到了BRCA1，在1995年找到了BRCA2。
于是他们就认为BRCA1和BRCA2的变异导致了乳癌。这个结论有多可靠呢？我看不到原始
数据，也不知道他们具体使用什么统计方法，不好下结论。但我自己是倾向于不相信。
有兴趣的朋友可以看一下我的另一个帖子
http://www.mitbbs.com/article0/ChineseMed/12638651_0.html
里面的“高尔夫球落点原理”一节，然后自己决定要不要相信。在我看来，他们所说的
携带BRCA1变异基因的人在70岁前生乳癌的概率是85%的这个数字和我在“高尔夫球落点
原理”一节里面计算出来的相关系数0.7848似乎有异曲同工之妙。
