A gonorrhea medicine used since the 1930s has shown an ability to halt the growth of blood vessels in cancerous tumors, scientists in Maryland say.

Preliminary tests showed mice engineered to develop cancer had no tumor growth if treated daily with the gonorrhea drug acriflavine, said Jun Liu, who teaches pharmacology and molecular sciences at Johns Hopkins University School of Medicine in Baltimore.

"Often times we are surprised that a drug known to do something else has another hidden property," Liu said in a recent issue of the Proceedings of the National Academy of Sciences.

Acriflavine stops blood vessel growth by inhibiting the protein hypoxia-inducible factor (HIF)-1, which turns on genes necessary for building new vessels, said Dr. Greg Semenza, director of the vascular program at the Johns Hopkins Institute for Cell Engineering.

"To continue growing, a tumor must create new blood vessels to deliver oxygen to the tumor cells," Semenza said.