FIG. 6.

Lefty2 KD cells develop immature malignant teratomas. (A) Lefty2 KD and control mESCs were injected into NOD/SCID mice and teratoma development was examined. The size of the teratomas was examined 6 weeks after injection. (B) H&E staining and data analysis of teratoma sections were performed by a pathologist. Immature neuroepithelium is indicated by dotted lines and mature neuroglia is indicated by green arrows (upper panel). Cartilage and bone in the teratoma are indicated by black and blue arrows, respectively (lower panel). (C) Quantification of immature neuroepithelium, mature neuroglia, epithelium, cartilage, bone, and muscle was performed using serially sectioned teratomas of two WT and two Lefty2 KD teratomas. (D) Oct4, Sox2, Nanog, Klf4, and Lefty2 expression in the teratoma tissue was analyzed by real-time RT-PCR. All values are mean±SD from at least three independent experiments. *P<0.05 based on Student's t-test analysis. KD, stable Lefty2-knocked-down mESC line; WT, wild-type mESCs.