TERC and teratoma: Furthermore, hematoxylin and eosin (H&E) staining of teratoma in the Terc−/− group failed to reveal cartilage, a mesoderm derived cell type that was observed in Terc+/− and wild-type groups; whereas cells for endoderm (e.g., ciliated epithelium) and ectoderm (e.g., neuron like) were observed in all groups (Figure 2F).