DNMT3B and embryonal carcinoma: De-novo DNMT, Dnmt3b, contributes to dynamic epigenetic reprogramming, especially in early mammalian embryogenesis,10 and is expressed in pluripotent cells, such as the inner cell mass and embryonic ectoderm cells of mouse embryos, and in isolated embryonic stem cells.25 Embryonal carcinomas also showed high-level expression of DNMT3B (Figure 2A,B).11,14,15 DNMT3B may be associated with cell pluripotency through its de-novo DNA methylation ability, not only during development but also in TGCTs.