Human Hepatocyte-Derived Induced Pluripotent Stem Cells: MYC Expression, Similarities to Human Germ Cell Tumors, and Safety Issues

Figure 6

iPSC generated from CD34+ hematopoietic stem cells. One of the three clones produced a partly solid tumor mainly composed (95%) of an embryonal carcinoma component (a, H&E 20x), with only rare neuroectodermal rosettes (arrow) and a minor yolk sac component (arrowheads). The yolk sac component consisted in a loose meshwork of primitive-appearing cells lining cystic spaces (arrow: neuroectodermal rosettes) (b, H&E 100x). Whereas strong reactivity for GPC3 (c, 200x) and AFP (d, 200x) was seen in the yolk sac tumor component, reactivity for OCT4 (e, 200x) highlighted the embryonal carcinoma component only. MYC staining was moderate in the embryonal carcinoma cells, whereas no reactivity was seen in the yolk sac component (f, 200x).

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