Steppa,
Wouldn't it be more interesting if we could discuss the mechanisms and science of this paper rather than say "lots of things have anticancer properties, those don't work cause people still die of cancer, we should probably add DMT to the list"
There are lots of ways different compounds that exert anticancer activity, and there are lots of different cancers stemming from different mutations in different tissues that respond differently to treatments. So yes, cancer is hard to treat. This is coming from someone who has personally worked in developing anti-cancer therapeutics, specifically against gliomas.
Frankly, we all likely have had small tumors occur inside us that have been killed by our immune system, and re-activation of the immune system against tumors is proving to be one of the most promising avenues of anti-cancer research at the moment. I personally trust an endogenous modulator of immune activity against something like cancer anyway, where the blunt knives of chemotherapy have often failed in the past due to the mutable and adaptive nature of cancer.
The authors propose relevant mechanisms by which DMT might act to modulate the immune system toward tumoricidal responses (inhibition of indole 2,3 dioxygenase) and other mechanisms involving the Sigma receptor and alteration of mitochondrial balance. It just seems pretty unfair to me to brush off these results as "pretty meaningless".
Do I think DMT is a magic bullet for cancer? No probably not, but it certainly might have positive effects, as suggested by this paper and other past studies. And I'm sure many people who have cancer would appreciate any sort of life extension.