angiogenin

noun

an·​gio·​ge·​nin ˌan-jē-ō-ˈje-nən, ˌan-jē-ˈä-jə-nən 

: any of several proteins that are ribonucleases produced both by normal cells (such as endothelium or smooth muscle cells) and by tumor cells and that promote the formation of blood vessels

Angiogenins were first discovered in 1985 when researchers found that the protein extracted from human cancer cells could stimulate the growth of blood vessels in experiments …

—Tina Hesman, The St. Louis Post-Dispatch