Additionally, we performed the teratoma formation assay using cells dissociated from the DRG explants cultured for 6 days in the presence of LIF/BMP2/FGF2, and found that teratomas were formed by injecting dissociated DRG cells treated with LIF/BMP2/FGF2 (Fig. 10A). Here, FGF2 is linked to teratoma.