Used primarily in the treatment of brain tumors, especially glioblastoma multiforme and other high-grade gliomas. It crosses the blood-brain barrier effectively, making it valuable in targeting central nervous system cancers. Also used in Hodgkin’s lymphoma and some other cancers when standard therapies fail. Administered orally, it works by alkylating DNA, which inhibits cancer cell replication and triggers cell death. Due to its delayed and cumulative bone marrow suppression, blood counts must be monitored closely during treatment.