[Growth and differentiation of human germ cell tumors: a possible model of embryogenesis]

Mouse embryonal carcinoma (EC) cells are the stem cells of teratocarcinoma. EC cells are malignant but have pluripotentiality like an early embryo. Therefore, mouse EC cell lines have been used to investigate the gene expression and its regulation in development and differentiation. On the other hand, human EC cells are considered to be the stem cells of human germ cell tumors. More than 50 cell lines derived from human germ cell tumors have been established since 1975. If human EC cells have pluripotentiality like mouse EC cells, human EC cell lines would be useful as an experimental model of human embryogenesis. We have investigated the cell biological characteristics of 3 kinds of cell lines derived from human germ cell tumors and have obtained the following results. 1) PA1/NR cell line derived from a patient with ovarian teratocarcinoma can grow in suspension and the spheroids are characterized by differentiation to primitive neuroectodermal rosette. 2) lMa cell line derived from a patient with ovarian dysgerminoma is consistent with choriocarcinoma. 3) NEC14 cell line derived from a patient with testicular EC/yolk sac tumor shows pluripotentiality.