HIF1A and glioblastoma: Studies have also demonstrated ELTD1 expression in GBM tissue itself, especially in the mesenchymal subtype, where receptor levels correlate with GBM progression and poor prognosis.115 Functionally, ELTD1 overexpression in established GBM cell lines promotes proliferation, migration, and invasion.116 Conversely, ELTD1 knockdown reduces GBM cellular viability,120 proliferation, and invasion capacity in vitro and decreases tumorigenesis in vivo, effects that are overcome by HIF-1α overexpression.116