Experimental design. Biopsy tissues from human gliomas are minced into small fragments that are subsequently cultured in medium. The tumour fragments remodel and form small tumour spheroids, usually within 1-2 weeks. These spheroids are stereotactically implanted in the nude rat brain, and form xenograft tumours (1st or low generation) that are harvested and processed similarly to the biopsy tissue. The resulting spheroids are passaged onto a new generation of rats and the previous steps can be repeated to passage the tumour for several generations.