This is an exploratory study to evaluate the clinical feasibility of medical deivce 'AVATAMED' for predicting the clinical response to TMZ (temozolomide) in glioblasotma patients.

Glioblastoma patients who would take TMZ treatment will be screened for in vitro drug screening experiment. Patients whose tumor specimen pass the drug screening process will be finally enrolled.

Actual clinical response to TMZ treatment will be compared to drug screening results derived from AVATAMED, a medical software device to predict the drug response based on in vitro assay using patient-derived tumor cells.

Inclusion Criteria:

1. written informed consent
2. histologically confirmed glioblastoma patients who will take TMZ treatment
3. KPS >70
4. adequte end-organ function
5. prior major surgery > 4 weeks (prior minor surgery > 1weeks)
6. prior standard concurrent chemo-radiation therapy > 4 weeks
7. prior radiation therapy (including stereotactic radiosurgery) > 12 weeks

Exclusion Criteria:

1. contraindication to TMZ
2. prior anti-cancer therapy except standard of care (*standard of care includes surgery, Stupp regimen, and radiotherapy)
3. uncontrolled systemic medical illness
4. pregnancy

among histologically confirmed glioblastoma patients, patients with samples which passed the QC screening process of in vitro drug screening experiment will be finally enrolled.