This is what I got when I googled "antineoplastic activity of cannabinoids".
http://www.ukcia.org/research/Antineopl ... /index.php
After a quick skim, it appears that certain THCs slow tumour growth rate in mice. Hmm. No cure, and I'm not sold on animal research results 100 percent because humans are not mice, and the mice are alone in cages, not in their natural environment meeting new mice to mate with and eating mice stuff.
A few other studies I've looked at make my head spin with the medical and chemical jargon.
We could be onto something here though.