The tumor must be located in the supratentorial compartment only (any component involving the brain stem or cerebellum is not allowed) Radiographic evidence of leptomeningeal dissemination, gliomatosis cerebri, infratentorial tumor, or disease at sites remote from the supratentorial brain. Histologically confirmed diagnosis of supratentorial glioblastoma. The tumor must be confined to the supratentorial compartment Tumor must be supratentorial only The tumor must be supratentorial Supratentorial mass effect with greater than 5 mm of midline shift or hydrocephalus Patients with treated supratentorial metastases are allowed if stable, the patient is off steroids and no evidence of intracranial hemorrhage Patients must have a recurrent supratentorial WHO grade III or IV malignant glioma based on imaging studies Prior histopathology consistent with a supratentorial WHO grade III or IV malignant glioma Patients must have a histologically confirmed diagnosis of supratentorial high-grade glioma or supratentorial ependymoma that is recurrent, progressive or refractory Subjects must have bi-dimensionally measurable disease, defined as at least one lesion that can be accurately measured in at least two planes\r\n* This disease must be located primarily in the supratentorial region\r\n* Patients with significant disease that is metastatic outside of the supratentorial region are ineligible Tumors must be supratentorial in location. The tumor must be primarily supratentorial in location as determined by diagnostic imaging performed preoperatively Evidence or suspicion of disease metastatic to sites remote from the supratentorial brain Supratentorial primitive neuroectodermal tumor (PNET) (any M-stage) will be eligible for study entry Imaging studies show evidence of recurrent, supratentorial tumor(s); the presence of infratentorial tumor is allowed as long as the patient also has supratentorial disease that is amenable to resection or biopsy Tumor must have a supratentorial component The tumor must be supratentorial in location Evidence or suspicion of disease metastatic to sites remote from supratentorial brain for intratumoral cohorts, supratentorial HGG (WHO grade III or IV) Elective craniotomy for supratentorial brain tumors Undergoing elective craniotomy for supratentorial tumors Location: supratentorial