Inclusion Criteria:

- Patients must have histologically or cytologically confirmed primary brain tumors
either benign or malignant), or histologically or cytologically confirmed primary
cancer with brain tumors that are consistent with brain metastases upon imaging, of
the following types:

- Group 1: Malignant brain tumors: glioblastoma multiforme, anaplastic gliomas,
brain metastases, and other malignant brain tumors

- Group 2: Low grade brain tumors: low grade gliomas, meningiomas (do not need
biopsy for radiographically diagnosed meningiomas), and other low grade brain
tumors including all other benign brain tumors

- All stages and grades of brain tumors are eligible

- Patients must have agreed to be treated with fractionated, external beam radiation
treatment (EBRT) with either curative or palliative intent (the length of the
radiation course must at least be ten fractions)

- Patients must have agreed to have computed tomography (CT) and magnetic resonance
(MR) imaging for purposes of radiation treatment planning, radiation treatment
monitoring, and/or radiation treatment evaluation

- Patients must have measurable disease using Magnetic Resonance Imaging

- Prior and concurrent therapies (cytotoxic, surgery, and radiation) are acceptable

- Use of steroids is acceptable when indicated

- Patients must be able to understand and willingly give informed written consent to
participate

- Women of childbearing potential must have a serum pregnancy test

- Patients must have a life expectancy of greater than 3 months

- Patients must be willing to comply with an oral treatment regimen and be able to
swallow oral study tablets

- Patients must have complete blood count, liver and kidney function panel within 2
weeks prior to registration

Exclusion Criteria:

- History of allergic reactions to pioglitazone or any other member of the
thiazolidinedione family

- Current diagnosis of diabetes as defined by fasting blood sugar > 125, treatment with
anti-diabetic medications (with the exception for insulin taken as a result of
steroid induced hyperglycemia), or history of diabetes

- Patients who have New York Heart Association (NYHA) class III or IV heart failure

- Patients who have elevated transaminases (aspartate aminotransferase [AST[ or alanine
aminotransferase [ALT] > 2.5 times normal limit)

- Patients who have significantly impaired renal function (creatinine >= 1.5)

- Patients who are significantly anemic (hematocrit < 33% in men, or < 30% in women)

- Patients who have symptomatic edema (>= grade 2)

- Patients who are on medications that have been shown to have a drug interaction with
pioglitazone: atorvastatin (doses > 80 mg/day), systemic anti-fungals, medications
with significant cytochrome P450 3A4 (CYP 3A4) inhibiting properties

- Uncontrolled intercurrent illness including, but not limited to, ongoing or active
infection, symptomatic congestive heart failure, unstable angina pectoris, cardiac,
arrhythmia, or psychiatric illness/social situations that would limit compliance with
study requirements

- Pregnant women will be excluded from this study because Pioglitazone is classified as
a pregnancy category C dug because it has been shown to cause toxicity to fetuses in
animals, but the effect is not well characterized in humans

- Patients with psychiatric or social illnesses that may impair compliance with the
trial requirements are to be excluded