Researchers have long searched for a way to inhibit blood vessel growth in tumors, a process known as angiogenesis that allows tumors to thrive and grow.

Now, in experiments in mice, scientists have been able to deliver a gene for an angiogenesis inhibitor into muscle, where it can be expressed and secreted into the bloodstream.

In the April issue of Nature Biotechnology, Doctor and colleagues at GeneMedicine, Inc. in The Woodlands, Texas, describe how they administered a gene encoding an angiogenesis inhibitor known as endostatin into the muscle of mice with kidney and lung tumors.

After a single injection of the gene, endostatin was detectable in the muscle and was secreted in the bloodstream for up to 2 weeks. What’s more, the compound inhibited both the growth of the primary tumors and metastases in other parts of the body.

But it is not clear whether the results of endostatin gene therapy will be similarly successful in humans, according to an accompanying editorial by Doctor Crystal of the Weill Medical College of Cornell University in New York.

However, the gene therapy may prove to be superior to the difficult process of producing large quantities of the endostatin protein outside the body and delivering it to tumors in sufficient quantities to be effective, he concludes.