1. Pathological confirmation or suggestion of adult-type diffuse gliomas A. Diagnosis includes glioblastoma, astrocytoma, oligodendrocytoma that is listed in ATDG category per WHO criteria.

   B. Gliomas that are preferred as ATDGs from pathological and clinical views, but not given for confirmed diagnosis.

2. Willingness to provide archival or newly obtained tumor tissues for current study proposal.

3. Age equal or more than 20 years old (inform consent).

4. Life expectancy more than 3 months.

5. Patients fully understand the protocol with the willingness to have regular follow-up.

6. Additional criteria for individual arms A. [Arm 1] Within 2 months after surgery for primary tumor. B. [Arm 2] Total resection of primary tumors with tissue samples available for test.

C. [Arm 3] (1) Total resection of primary tumors with the paired primary and recurrent tissue samples available for test. (2) IDH test suggesting wild-type.

1. Gliomas diagnosed or preferred as other categories than ATDGs, such as pediatric-type diffuse gliomas, circumscribed astrocytic gliomas, and others.
2. Inability to cooperate by providing a complete medical history.
3. Patients disagree to provide archived tumor samples.
4. Undesirable compliance.
5. Having a known additional malignancy that is progressing or has required active treatment within the past 3 years. Participants with basal cell carcinoma of the skin, squamous cell carcinoma of the skin, or carcinoma in situ (e.g., cervical carcinoma in situ) that have undergone potentially curative therapy are not excluded.