"What they found is that the cannabinoid turns off

"What they found is that the cannabinoid turns off the overexpression of ID-1, which makes the cells lose their ability to travel to distant tissues. In other words, it keeps the cells more local and blocks their ability to metastasize. Cancer kills through its ability to metastasize."

http://www.sfgate.com/health/article/Pot-comp...875562.php