Why are systemic glioblastoma metastases rare? Systemic and cerebral growth of mouse glioblastoma

Delayed brain tumor cells implanted outside the CNS formed tumors unless there was a significant difference between the immunotype of the implanted cells and host. These results support the hypothesis that the rarity of systemic GBM tumors lies in the presence of physical barriers and/or systemic hurdles that prevent their timely growth. These results also demonstrate that GBMs are antigenic, although not immunogenic, with their syngeneic host. Therefore, GBM may be amenable to targeted immunotherapy given successful artificial priming of the immune system.