乳腺癌易感基因

BRCA-1 和 BRCA-2是与遗传性乳癌和卵巢癌相关的两个基因。根据美国癌症协会资料显示，每年约20万妇女被诊断为浸润性乳腺癌，约2.3万被诊断为卵巢癌。在这些癌症中，大约5%-10%是由于BRCA基因中的一个位点发生了变异引起的。男性也可能由于BRCA-2基因的改变导致发生乳癌的遗传性风险增加。

        发生BRCA1或BRCA2突变的个体，其患乳癌（一生风险度最高至80%）、卵巢癌（一生风险度最高至40%）、双乳癌以及其他癌症风险度显著增加。BRCA突变是遗传性获得的并且可以代代相传。有一半的机率，这些基因是由父方家族传下来的。

        BRCA基因突变可以用血细胞中的DNA来检测。虽然BRCA基因的产物（蛋白）只在乳腺和卵巢组织中起作用，但是基因在身体内的任何细胞中都有表达，其中血液是获取DNA来源最简便易行的样本。

用于做BRCA基因突变的血标本是自肘静脉采集得到的。此试验不需要做乳腺或者卵巢组织的手术活检。

疾病: 乳腺癌, 卵巢癌
新闻要事: BRCA Genetic Test Misses Some Mutations (2006)

National Cancer Institute
American Cancer Society
American Society of Clinical Oncology
National Breast Cancer Coalition

Original Source

S1
Fasouliotis SJ and Schenker JG. BRCA1 and BRCA2 Gene Mutations: Decision-Making Dilemmas Concerning Testing and Management. Obstetrical and Gynecological Survey 55(6); 373-384 (2000).

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(2005 July 18, Updated). Fact Sheet on Genetic Testing for Breast and Ovarian Cancer Susceptibility [31 paragraphs]. CDC Genomics and Disease Prevention [On-line information]. Available FTP: http://www.cdc.gov/genomics/info/factshts/breastcancer.htm

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(2005 September). Genetic Risk Assessment and BRCA Mutation Testing for Breast and Ovarian Cancer Susceptibility [6 paragraphs]. U.S. Preventive Services Task Force [On-line Press Release]. Available FTP: http://www.ahrq.gov/clinic/uspstf/uspsbrgen.htm

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Petrucelli, N. et. al. (2004 September 3). BRCA1 and BRCA2 Hereditary Breast/Ovarian Cancer]. GeneReviews [On-line information]. Available online

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S9
Brian E Ward, Ph.D. FACMG
Senior Vice President of Medical Services
Myriad Genetic Laboratories