A new study says that a drug commonly used to treat breast cancer can be used to prevent other cancers from spreading through the body.

The drug - geldanamycin - works by attacking a protein associated with the spread of breast cancer. A new study led by researchers from University of Leeds has found that the drug can also stop the growth of blood vessels by attacking another protein. Once the blood supply is cut, the tumor's growth slows down.

"This is potentially very significant because tumours secrete substances that stimulate blood vessels to develop around them, forming networks that supply nutrients and provide pathways for spread around the body. This is one of the big problems in cancer: how can we stop the tumour growing and spreading through these blood vessel networks?" said Dr. Sreenivasan Ponnambalam, reader in human disease biology in the University of Leeds' Faculty of Biological Sciences.

Other drugs that stop blood vessel growth are available but these target a protein found in the membrane called VEGFR2. Targeting this protein carries serious side effects as the protein is associated with other functions like blood pressure control.

"With conventional treatments, we have been trying to deal with the situation after the switch has been thrown. What this drug does is destroy the key part of the switch before that switch is thrown," Dr. Ponnambalam said.

The study was conducted on human cell-lines and animal cells. Researchers found that the drug indirectly stopped VEGFR2 protein by accelerating "quality-control system" that degrades many proteins.

The quality control system slowly breaks down certain proteins; the new drug quickens this process and thus stops new unwanted blood vessels from forming.

"Geldanamycin and chemical derivatives have been under intensive study in the laboratory and in clinical trials for the past 20 years," Dr. Ponnambalam added.

The study is published in the journalĀ PLOS ONE.