For people they are in the minority, but the causes of other cases are unknown. Both of these also increase the risk of adrenal tumors in humans. (Yes, I was searching around in work on non-ferrets again, because sometimes what is learned from one type of being translates to another. Rates of genetic risk factors also vary among species.) http://www.cancerresearchuk.org/cancer-help/about-cancer/cancer-questions/insulinomas QUOTE Risks and causes of insulinoma We don't know what causes most insulinomas. Between 5 and 10 out of every 100 people with insulinoma (5 to 10%) have a rare family syndrome, either multiple endocrine neoplasia type 1 (MEN 1) or von Hippel-Landau syndrome. END QUOTE In ferrets all that we have so far are hypotheses for possible causes of insulinoma but I know that at least one of these two genetic risk factors has been among things being studied by a veterinary professor to see if it might apply for ferrets. It will be interesting to find it either or both of these genetic vulnerabilities exist in pet ferrets and then later to what degree. There is still a great deal to learn about insulinoma in all species that get it, and no additional answers showing up so far with rigorous studies. That vulnerability to insulinoma in ferrets might have at least one genetic component is absolutely no surprise for any of us who have been in the ferret world for 25+ or 30+ years because before fancies were so common endocrinological tumors, especially ones before very old age, were also far less often reported, ditto the symptoms of such problems. They happened, yes, but less often. (Two problems which seemed to have been reported more often then compared to now were splenic rupture, which is avoidable now due to infection types and treatments being documented, and lymphoma. So, it was not all wine and roses but non-fancy ferrets also seemed to have longer lives than many now report after so much in the way of fancy genetics wound up in the breeding lines.) In veterinary reports from Europe and notes from people there to lists there appear to be similar increases in certain health problems as fancies become more common. Oh, and on that score. From a longtime Maryland breeder, Danee DeVore, we have a six year old, standard marking, spayed female ferret who recently was mistaken at a vet hospital for a three year old and who remains very strong, very happy, and completely healthy. Hopefully, Pivot has a good many more years in her. The only thing we have to watch in her is an increased vulnerability to dental tarter due to her teeth having large cingulae (which make the teeth stronger against breakage but capture more debris). Of course, for a few years we also have been among those who have been trying annual springtime Suprelorin implants in all of our ferrets, too. It is costly, but has a very good chance of being extremely good for the ferrets. [Posted in FML 8103]