I don't know that I would call en vitro studies promising. Cancer would be long be a solved problem if even a tenth of the stuff that kills cancer cells in a petri dish was viable in humans.
It's not just *in vitro.
Per article (and not arguing it's effective for human oncology), there are also studies with mice showing effectiveness.
It's not just *in vitro.
Per article (and not arguing it's effective for human oncology), there are also studies with mice showing effectiveness.