Although the spheres in this study described were capable of generating teratoma-like tissue, the transplanted cells did not form large teratomas as did ES cells, nor they did express Eras in vitro as ESCs,[31] which suggests that the teratoma-like tissue they generate may be very different from true teratomas generated from ESCs. In addition, the cells studied did not express the trophectoderm marker Cdx2[32 ]or also associated with ESCs. These differences of gene expression pattern may explain the differences of the biological function between ESCs and adult stem cells in this study.
参考文献の31と32は以下よ。
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31. Takahashi, K., Mitsui, K., and Yamanaka, S. Role of ERas in promoting tumour-like properties in mouse embryonic stem cells. Nature 423, 541, 2003.
32. Ralston, A., and Rossant, J. Genetic regulation of stem cell origins in the mouse embryo. Clin Genet 68, 106, 2005.