Our finding of ANGPT1 upregulation as a prolonged response to chronic radiation in the highly infiltrative and radio-resistant STIC (with DM) subpopulation of GBM supports the rationale of using an inhibitor of ANGPT1/TEK following radiotherapy to suppress angiogenesis, and hinder the development of recurrent GBM. The gene discussed is ANGPT1; the disease is glioblastoma.