Cyrus Ghajar

Cyrus Ghajar discovered that disseminated tumor cells reside in perivascular niches where endothelial-derived thrombospondin-1 maintains their dormancy, and showed that sprouting angiogenesis (neovascular tip cells) disrupts this dormancy signal to trigger metastatic outgrowth. His work revealed that the stable microvasculature actively suppresses DTC proliferation through thrombospondin signaling while growing vessels provide permissive signals including TGF-beta1 and periostin that awaken dormant cells. He has characterized how bone marrow perivascular niches specifically harbor dormant breast cancer DTCs for extended periods. His niche-centric view of dormancy has identified endothelial biology as a key therapeutic intervention point.