A method of intracranial transplantation of the tumor induced by adenovirus type 12 in syrian hamster has been described. The incidence of intracranial tumor development was 86 (90.5 %) out of 95 animals and the average survival time and tumor size at death were 15.1 days and 4.1
mm in diameter respectively. The consistency of the days of death after intracranial transplantation of the tumor was remarkable. The transplanted tumors developed preferentially at the site of implantation and tumor
cell seeding and tumor growing took place rarely along the ventricular system. Glial or lymphoid cell response to the tumor was not observed at any stage after transplantation in surrounding cerebral tissues of the animals.
Histomorphologically, no elementary differences were observed between intracranially transplanted tumors and serially transplanted subcutaneous tumors.
These facts permit the system to be applied to an experimental brain tumor model as large-scale testing.</p