Untested Cancer Drug Sold Online

The drug, called DCA, has been shown to shrink tumours in rats but tests on humans are years away.

However Nature magazine reports some terminally ill patients are taking the drug because they do not want to wait for the research.

UK cancer experts warned patients there was no evidence DCA was beneficial, and said it could cause harm.

DCA, or dichloroacetate, is a small molecule that blocks an enzyme in mitochondria - which generate energy in cells and also control cell suicide.

Dr Evangelos Michelakis, of the University of Alberta in Canada, who has been investigating the drug, found the cancer cells turned off the suicide switch.

Tests he carried out on rats showed DCA can reignite the switch, and prompt the cells to die.

Tumours shrank by around 75% within three weeks.

Other work has shown DCA can kill human cancer cells in the lab, but no patients have actually been given the drug to treat their cancer.