We have developed xenografts of human glioblastoma (GBM) and established the baseline growth parameters and histopathological features of these tumors. Cells from 4 different human GBM cell lines were injected into the right caudate-putamen of brain in athymic rats. We measured tumor weights and the estimated survival time of each rat. RESULTS-CONCLUSION: U-251 MG and U-87 MG cells produced solid intracerebral tumors with a 100% tumor take rate, while SF-767 and SF-126 cells did not grow in the brains of athymic rats. Under the conditions employed, U-87 MG tumors grew faster than U-251 MG tumors, but both types of tumors exhibited reproducible growth characteristics from animal to animal. There was heterogeneity in the growth characteristics and histologies between the 2 tumor types, indicating that these tumor models might be useful for simulating some of the heterogeneity that occurs between GBM in humans.