How do we leverage the increasing amount of genetics and genomics data to better diagnose, classify and treat brain tumors? We investigated ancestry-based genomic signature differences in patients with malignant brain tumors and the implications for clinical trial design in these incurable diseases. We also looked at various biomarkers that can non-invasively but accurately diagnose, prognose and classify brain tumors — including viral infection history, hematological parameters and immune system parameters. These studies collectively contributed to personalized and minimally-invasive diagnostic processes for malignant brain tumors and point to more effective patient stratification strategies for clinical trials.