PAX8 and pilocytic astrocytoma: To confirm the prevalence of increased PAX8 expression in primary glioblastomas, PAX8 expression was analyzed using QPCR in 40 glioblastoma samples (30 positive and 10 negative by IHC), recurrent pilocytic astrocytomas, PAX8-positive grade II astrocytomas, human fetal astrocytes derived from an 18-week gestated fetus (PAX8-positive control), and HEK-293 cells (no or low PAX8 expression).