(A1, A2) LCAS-R 2nd nsphrs/LCAS-RTL(138) 2nd nsphr, (A3) Tubb3 40x LCAS-RTL(138) 2nd nsphr, (A4) GFAP 40x LCAS-RTL(138) 2nd nsphr; (B1, B2) HE 40x LCAS-R/LCAS-RTL(138) - images show undifferentiated small round blue cells with scarce cytoplasm, (B3) HE 40x (LCAS-RTL(138) SVZ 15 weeks post-injection) - extensive proliferation of undifferentiated embryonal tumor cells infiltrating the adjacent brain parenchyma, (B4) Ki67 40x (LCAS-RTL(138) SVZ 15 weeks post-injection) - high proliferative activity of tumor cells is reflected by over 75% of cells expressing Ki-67, (C1) OCT3/4 40x (LC26-RTL(170) SVZ 12 weeks post-injection) - extensive proliferation of tumor cells invading adjacent brain parenchyma show high expression of OCT3/4 (over 80% of cells), (C2) Sox2 40x (LC26-RTL(170) SVZ 12 weeks post-injection) - extensively expressed in the tumor cells, (C3) PRAME 40x (LCAS-R 12 weeks post-injection) - extensively expressed in the tumor cells, (C4) Nestin 40x (LCAS-RTL(138) 15 weeks post-injection) - extensively expressed in the tumor cells, (D1) Vimentin 40x (LCAS-RTL(138) 15 weeks post-injection) - extensively expressed in the tumor cells within the main tumor mass and in the invading areas, (D2) BLBP 40x (LC26-RTL(170) 16 weeks post-injection) - extensively expressed in the tumor cells, (D3, D4) OTX2 20x, 40x (LC26-RTL(170) 16 weeks post-injection) - extensive expression (over 80% of cells) in tumor cells. TU-tumor; P-parenchyma; PI- perivascular invasion.