Yes, good point. In vivo research either requires mice to grow their own tumors or to have human tumors implanted into them. A disgusting process that makes animal research not vegan, and that's sad...I'm not quite sure how to feel about that right now, but I think the first step is to research if alternatives are available, and then to advocate human clinical trials for cannabis as a cancer treatment, since it's proven safe and effective enough pre-clinically (moreso than anything we currently have available) and would reduce the amount of animal suffering all-round.

This is not a good link, though. I only understood what this meant because I've done a bit of research about research methodology, pun intended ;) Even for people who understand the reference, this link doesn't provide any helpful information. It's kind of just like name dropping.