Figure 1.

Tumor cell distribution in the transplanted hemisphere of GIC-derived tumors.

Fluorescence microscopy images of immunolabeled coronal sections from GIC-derived tumors derived from T08, T11, T25 or T65 cultures. (A) T08 formed tumors with a large tumor core and moderate tumor cell migration mainly along white matter tracts (corpus callosum and anterior commissure) (white arrows). (B) Vimentin-labeling (red) of invasive tumor cells showed an accumulation of tumor cells in the septal area and the subpial lining (interhemispheric fissure) – not contiguous with the tumor core- covering the medial surfaces of both hemispheres. Tumor-infiltrated regions were divided in areas adjacent (red arrows) and non-adjacent (white arrows) to the tumor core. Counter-staining with a human-specific mitochondrial antibody (hMit) (green). (C) T25 xenograft tumors with a large tumor core and bihemispheric tumor invasion. (D) T65 displayed a much smaller tumor core with extensive intraparenchymal invasion and distribution of tumor cells resembling a butterfly glioma. (E-G) The thalamus and septal areas were frequently invaded by tumor cells. The subependymal lining was infiltrated (A-C), and even when tumor cores were not contiguous with the subventricular zone, tumor cells were detected on the contralateral side. (H-J) Certain brain regions adjacent to the tumor core, such as the hypothalamus, amygdala and hippocampus, were rarely invaded. (J) The white matter surrounding the hippocampus was packed with tumor cells, whereas the cornu ammonis and the dentate gyrus were spared.

Abbreviations: aca, anterior part of anterior commissure; AMG, amygdala; alv, alveus; CA, cornu ammoni; cc, corpus callosum; cp, cerebral peduncle; CPu, caudate putamen; D3V, dorsal part of the third ventricle; DG, dentate gyrus; fi, fimbria; HPC, hippocampus; HY, hypothalamus; ihf, interhemispheric fissure; Or, oriens layer of the hippocampus; Py, pyramidal layer of the hippocampus; py, pyramidal tracts; TC, tumor core; TH, thalamus; * lateral ventricle.