This is a myth, one would assume, that exists because bison do not age to the point where they would more commonly experience cancer, and that it would be too expensive to maintain adult bison under laboratory controlled conditions to investigate whether or not the assertions are valid.
There are also multiple instances of bison having either carcinoma or papilloma at branding sites http://vdi.sagepub.com/co
It is likely that the urban legend of both bovine and shark cartilage curing/preventing cancer has a common origin in the research of a single person: Dr. John F Prudden. http://www.nytimes.com/19
Prudden first started with bovine cartilage, which probably led to grapevine stories about both the cartilage and underlying animals, including cattle (bos) and bison, and later moved on to shark cartilage, which was demonstrated in vitro to have greater anti-angiogenic activity as well as having a greater percentage of mass as cartilage, likewise creating grapevine stories about the incidence and protective effect on sharks. See: The coincidence of the stories centering around this single, notable figure and the timeframe for these myths makes it reasonable that all of these are somehow related.
It is informative that the company founded to commercialize Prudden's work has withered to a small cosmetic nutraceutical firm, Lescarden, with <$0.5m in revenuehttp://www.pharmaceutical
Likewise, Aeterna Zentaris (AeZ) attempted clinical trials of shark cartilage, with no apparent benefit to tumor reduction and no full published results of the trial.http://www.ncbi.nlm.nih.g