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Atypical teratoid rhabdoid tumor (AT/RT) is a rare tumor usually diagnosed in childhood. Although usually a brain tumor, AT/RT can occur anywhere in the central nervous system (CNS) including the spinal cord. About 60% will be in the posterior cranial fossa (particularly the cerebellum). One review estimated 52% posterior fossa, 39% sPNET (supratentorial primitive neuroectodermal tumors), 5% pineal, 2% spinal, and 2% multi-focal.〔 〕 In the United States, three children per 1,000,000 or around 30 new AT/RT cases are diagnosed each year. AT/RT represents around 3% of pediatric cancers of the CNS.〔(Measure D6: Types of Childhood Cancer ) – 2006 Tables D6a & D6b. U.S. Environmental Protection Agency. Retrieved on 2008-04-17.〕 Around 17% of all pediatric cancers involve the CNS; it is the most common childhood solid tumor. The survival rate for CNS tumors is around 60%. Pediatric brain cancer is the second leading cause of childhood death, just after leukemia. Recent trends suggest that the rate of overall CNS tumor diagnosis is increasing by about 2.7% per year. As diagnostic techniques using genetic markers improve and are used more often, the proportion of AT/RT diagnoses is expected to increase. AT/RT was only recognized as an entity in 1996 and added to the World Health Organization (WHO) Brain Tumor Classification in 2000 (Grade IV). The relatively recent classification and rarity has contributed to initial misdiagnosis and non-optimal therapy. This has led to a historically poor prognosis.〔 See Figure 1.〕 Current research is focusing on using chemotherapy protocols that are effective against rhabdomyosarcoma in combination with surgery and radiation therapy. Recent studies using multi-modal therapy have shown significantly improved survival data. In 2008, The Dana-Farber Cancer Institute in Boston reported two-year overall survival of 53% and event-free survival of 70% (median age at diagnosis of 26 months). In 2013, The Medical University of Vienna reported five-year overall survival of 100%, and event-free survival of 89% (median age at diagnosis of 24 months). Survival rates can be significantly improved when the correct genetic diagnosis is made at the outset, followed with specific multi-modal treatment. ==Classification== AT/RT may be related to malignant rhabdoid tumor (MRT), which occurs outside the CNS, usually in the kidney. The finding that AT/RT and MRT both have deletions of the INI1 gene indicates that rhabdoid tumors of the kidney and brain are at least closely related. AT/RT and MRT also have similar histology and similar clinical and demographic features. Moreover, 10–15% of MRT patients have simultaneous or subsequent brain tumors, many of which are secondary or primary MRT. 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「Atypical teratoid rhabdoid tumor」の詳細全文を読む スポンサード リンク
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