ANGPT1 and primary brain neoplasm: Ang-2 is an important angiogenic regulator that is critically involved in destabilizing the microvasculature and promoting angiogenesis by competing with angiopoietin-1 for Tie-2 receptor binding.38,39 As such it has been identified as a key regulator of cancer cell propagation and tumor growth in several types of cancer, including breast and colorectal cancer, renal cell carcinoma, and melanoma.40–43 Furthermore, Ang-2 is critically involved in the development and outgrowth of brain cancer, including primary brain tumors such as glioblastoma,20,21 and BM.