UK scientists have found that a type of drug designed to stunt tumor growth can actually encourage cancer if given at too low a dose.
They looked at angiogenesis inhibitors designed to block the supply of blood to tumors to prevent them from growing.
For their study, the scientists studied an experimental angiogenesis inhibitor called Cilengitide that has yet to be licensed for patients.
Tests conducted on mice showed that low doses of Cilengitide actually stimulated the growth of cancers.
Further research showed it did this by switching on a molecule called VEGFR2, which triggers the angiogenesis process.
That is significant because although when a patient is initially given a drug, its level in the blood rises quickly ensuring a big dose goes to the tumor, after a while levels start to fall as the body begins to deal with the drug.
Dr. Kairbaan Hodivala-Dilke of the Institute of Cancer, who led the study, said it was important that the trials looking at this drug continued.
"We've got evidence now that low doses can enhance tumor growth. So there is no benefit of giving a high dose, which then drops, and then a high dose again. But that's not to say it can't work at all. It can, but there is this caveat," the BBC quoted Hodivala-Dilke, as saying.
The study has been published in Nature Medicine.