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''BRCA2'' and BRCA2 () are a human gene and its protein product, respectively. The official symbol (BRCA2, italic for the gene, nonitalic for the protein) and the official name (breast cancer 2, early onset) are maintained by the HGNC. Orthologs, styled ''Brca2'' and Brca2, are common in other mammal species. ''BRCA2'' is a human tumor suppressor gene (specifically, a caretaker gene), found in all humans; its protein, also called by the synonym breast cancer type 2 susceptibility protein, is responsible for repairing DNA. BRCA2 and BRCA1 are normally expressed in the cells of breast and other tissue, where they help repair damaged DNA or destroy cells if DNA cannot be repaired. They are involved in the repair of chromosomal damage with an important role in the error-free repair of DNA double strand breaks. If BRCA1 or BRCA2 itself is damaged by a BRCA mutation, damaged DNA is not repaired properly, and this increases the risk for breast cancer. Thus, although the terms "breast cancer susceptibility gene" and "breast cancer susceptibility protein" (used frequently both in and outside the medical literature) sound as if they describe a proto-oncogene or oncogene, ''BRCA1'' and ''BRCA2'' are "normal"; it is their mutation that is abnormal. The BRCA2 gene is located on the long (q) arm of chromosome 13 at position 12.3 (13q12.3). The human reference BRCA 2 gene contains 28 exons, and the cDNA has 10,254 base pairs〔(【引用サイトリンク】 BRCA2 breast cancer 2, early onset (sapiens ) )〕 coding for a protein of 3418 amino acids.〔(【引用サイトリンク】 Breast cancer type 2 susceptibility protein - Homo sapiens (Human) )〕 The gene was first cloned by scientists at Myriad Genetics, Endo Recherche, Inc., HSC Research & Development Limited Partnership, and the University of Pennsylvania. Methods to diagnose the likelihood of a patient with mutations in BRCA1 and BRCA2 getting cancer were covered by patents owned or controlled by Myriad Genetics. Myriad's business model of exclusively offering the diagnostic test led from Myriad being a startup in 1994 to being a publicly traded company with 1200 employees and about $500M in annual revenue in 2012;〔(Myriad Investor Page—see "Myriad at a glance" ) accessed October 2012〕 it also led to controversy over high prices and the inability to get second opinions from other diagnostic labs, which in turn led to the landmark ''Association for Molecular Pathology v. Myriad Genetics'' lawsuit. == Function == Although the structures of the BRCA1 and BRCA2 genes are very different, at least some functions are interrelated. The proteins made by both genes are essential for repairing damaged DNA. BRCA2 binds the single strand DNA and directly interacts with the recombinase RAD51 to stimulate strand invasion a vital step of homologous recombination. The localization of RAD51 to the DNA double-strand break requires the formation of BRCA1-PALB2-BRCA2 complex. PALB2 (Partner and localizer of BRCA2) can function synergistically with a BRCA2 chimera (termed piccolo, or piBRCA2) to further promote strand invasion. These breaks can be caused by natural and medical radiation or other environmental exposures, but also occur when chromosomes exchange genetic material during a special type of cell division that creates sperm and eggs (meiosis). Double strand breaks are also generated during repair of DNA cross links. By repairing DNA, these proteins play a role in maintaining the stability of the human genome and prevent dangerous gene rearrangements that can lead to hematologic and other cancers. Like BRCA1, BRCA2 probably regulates the activity of other genes and plays a critical role in embryo development. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「BRCA2」の詳細全文を読む スポンサード リンク
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