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4. Eble, J.N., Sauter, G., Epstein, J.I. & Sesterhen, I.A. (eds). in World Health Organization Classification of Tumours, Pathology & Genetics: Tumours of the Urinary System and Male Genital Organs 217278 (IARC Press, Lyon, France, 2004).
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Nature Biotechnology responds:A survey of the literature indicates no consensus on how to distinguish the terms teratoma and teratocarcinoma. The term teratocarcinoma is used as a synonym for human tumors clinically known as teratoma with embryonal carcinoma (accordingto the World Health Organization) or teratoma intermediate (according to the British classification of germ cell tumors). Some pathologists include these tumorsin the group of testicular nonseminomas (also known as nonseminomatous germ cell tumors (NSGCT)) or use imprecise terms, such as malignant teratoma. The somatic tissues in teratocarcinoma may be fully differentiated (equivalent to adult tissue) or only partially differentiated (corresponding to immature tissues in fetal organs).
On the basis of the above exchangeand after expert consultation, Nature Biotechnology will adopt the term teratocarcinoma to describe malignant tumors comprising both somatic tissuesand undifferentiated malignant stem cells, identifiable as EC cells. EC cells are malignant equivalents of ES cells. Human EC cells should be identifiable microscopically according to the pathologic and immunohistochemical criteria used to identify human EC cellsin malignant germ cell tumors of theovary or testis or extragonadal sites. In an experimental setting, the malignancy of a tumor due to the presence of morphologically identifiable undifferentiated EC cells may be defined by their ability to form a new tumor after transplantation to a new host.
We will apply the term teratoma onlyto tumors composed of normal, benign somatic tissue and their immature (fetal) precursors derived from more than one of the...