11 Embryonal Carcinoma Cells as Embryonic Stem Cells

Abstract

Embryonal carcinoma (EC) cells are the stem cells of teratocarcinomas. These tumors, which present a caricature of embryogenesis, have fascinated pathologists for many hundreds of years. Indeed, Wheeler (1983), in his excellent review of the history of these tumors, mentions that the earliest reference to what is evidently a teratoma, a benign form, is found on clay tablets from the Chaldean Royal Library of Nineveh dating from 600 to 900 B.C. Among these tablets, devoted to methods of predicting the future, one sign is described, “When a woman gives birth to an infant that has three feet, two in their normal position (attached to the body), and the third between them, there will be great prosperity in the land” (Ballantyne 1894). Such an optimistic forecast perhaps foretells the value that modern biologists have found in EC cells as tools for the study of cell differentiation in embryonic development and cancer.

Teratomas and teratocarcinomas occur in a range of manifestations (Table 1). The most common are ovarian dermoid cysts. These form from oocytes that are parthogenetically activated and begin development but eventually become disorganized, giving rise to a teratoma containing a haphazard array of embryonic tissues (Fig. 1). Such tumors are generally benign, but they can grow to very large sizes. Teratomas also occur, although more rarely, in other sites, including the base of the spine in newborn infants, and it is a tumor of this type that is evidently the subject of the Chaldean writer.

Of greater clinical significance to...