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Triple-negative breast cancer (sometimes abbreviated TNBC) refers to any breast cancer that does not express the genes for estrogen receptor (ER), progesterone receptor (PR) or Her2/neu.〔(article ); NEJM〕 This makes it more difficult to treat since most chemotherapies target one of the three receptors, so triple-negative cancers often require combinatorial therapies (see below). Triple negative is sometimes used as a surrogate term for basal-like; however, more detailed classification may provide better guidance for treatment and better estimates for prognosis. Triple-negative breast cancers comprise a very heterogeneous group of cancers. There is conflicting information over prognosis for the various subtypes but it appears that the Nottingham prognostic index is valid and hence general prognosis is rather similar with other breast cancer of same stage, except that more aggressive treatment is required. Some types of triple-negative breast cancer are known to be more aggressive with poor prognosis, while other types have prognosis very similar or better than hormone receptor positive breast cancers. Pooled data of all triple-negative subtypes suggest that with optimal treatment 20-year survival rates are very close to those of hormone positive cancer.〔 Triple-negative breast cancers have a relapse pattern that is very different from hormone-positive breast cancers: the risk of relapse is much higher for the first 3–5 years but drops sharply and substantially below that of hormone-positive breast cancers after that. This relapse pattern has been recognized for all types of triple-negative cancers for which sufficient data exists although the absolute relapse and survival rates differ across subtypes.〔〔 ==Classification== Triple-negative breast cancers (TNBC) are sometimes classified into "basal-type" and other cancers; however, there is no standard classification scheme. Basal type cancers are frequently defined by cytokeratin 5/6 and EGFR staining. However, no clear criteria or cutoff values have been standardized yet.〔 About 75% of basal-type breast cancers are triple negative. Some TNBC overexpresses epidermal growth factor receptor (EGFR).〔Feb 2009 Breast Cancer Watch〕〔(【引用サイトリンク】title=Understanding and Treating Triple-Negative Breast Cancer )〕 Some TNBC over expresses transmembrane glycoprotein NMB (GPNMB). Upon histologic examination, triple-negative breast tumors mostly fall into the categories of ''secretory cell carcinoma'' or ''adenoid cystic types'' (both considered less aggressive); ''medullary cancers'' and grade 3 invasive ''ductal carcinomas'' with no specific subtype; and highly aggressive ''metastatic cancers''.〔 Medullary TNBC in younger women are frequently ''BRCA1''-related. Rare forms of triple-negative breast cancer are ''apocrine'' and ''squamous carcinoma''. ''Inflammatory breast cancer'' is also frequently triple negative. Many proteins such as Caveolin 1/2, Survivin are researched as possible classification or prognostic factors. 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「Triple-negative breast cancer」の詳細全文を読む スポンサード リンク
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