This is a great step forward, as existing chemotherapy involves inhibiting cell division and usually results in cross-resistance to all agents. Hydrogen sulfide and related compounds would avoid this by inhibiting mitochondrial function instead. Furthermore, the small molecular size and high solubility of these compounds means they would be able to penetrate the altered membranes of resistant cancer cells.
As far as possible treatment protocols are concerned, one might be to administer a hydrogen sulfide producing compound through a hepatic drug port to treat liver metastases. The hydrogen sulfide would then be exhaled. Hydrogen sulfide could also be administered by inhalation. In his research published in SHOCK in 2005 and reprised in SCIENCE later that year, Mark Roth showed that inhaled hydrogen sulfide could be used to place mice in a coma from which they would then recover.
Regarding the paradoxical effect in colorectal carcinoma cells which they found so difficult to explain, the actual reason might be enzymes which detoxify hydrogen sulfide which might be emitted by intestinal bacteria. The solution might be other mitochondrial poisons like cyanide. This may seem madness; however it is plausible that the purported effect of Laetrile, usually dismissed as quackery, might be a genuine effect of the cyanide emitted. The treatment protocol here might be administration through a hepatic drug port with glutathione along with systemic administration of hydroxycobalamin.
Animal testing should commence immediately.