Sharks Get Cancer, Mole Rats Don’t by James S. Welsh, MD (book review)

James S. Welsh’s book title ‘Sharks Get Cancer, Mole Rats Don’t’ is enhanced by the sub-title, ‘How Animals Could Hold The Key To Unlocking Cancer Immunity In Humans’. After all, our species isn’t the only one to get cancer. What is more remarkable is that some species get cancer and then not only go into remission but cleared of it as well. Just as you would with an infection, which as he points out some cancers are just that. As with all infections, if cancer is a parasitical illness, why kill the host? I had a serious think about that and wondered if we’re actually seeing evolution in action. Wouldn’t whatever is the preferred hosts be the preference and, over generations, actually remove members of the species that wouldn’t work? This doesn’t mean the cancer is sentient to realise that but, as an evolutionary preference, it would make a lot of sense. Considering how long evolution of a species, outside of mutation, takes, we’re essentially work in progress.


Anyway, I digress, let’s look further into the book. Welsh looks at the Tasmasian Devil, a marsupial that is rapidly becoming extinct by a facial tumour disease killing some 80% of its population. The cause is them fighting amongst themselves and their bites passing the cancerous growth from one to the other. The outbreaks of ebola are only periodical in humans, although not passed by biting but are passed from species to species, not helped by deforestation. Slightly more amusing is a cancer called canine transmitted veneral tumour (CTVT) that domestic dogs get that will cure itself, with some vets wanting to be seen to act quickly with chemo or radiation to take credit for the ‘cure’. Don’t forget, tumours are what we see as cancer. Welsh also describes how, after some chemo and radiation treatment, that some people have total remission as well. For those suffering from cancer, I think Welsh would probably agree with me that you shouldn’t raise your hopes too high if you do have cancer as a lot of this depends on your immune system reacting and it doesn’t in most of the population.

Cancer is also not something of recent times. Even dinosaur bones have been found containing metastatic cancer. As Welsh also points out, the size or growth of the animal has nothing to do with getting cancer or surely blue whales and elephants would never have survived.

Once Welsh started going through the species that got cancer, including invertebrates, it was more a question of what doesn’t. He disposes of sharks being immune to cancer from trails and a photo in the insert verifies it. There are some separate species are cancer free. The hairless mole rats that belong to the porcupine family and the similarly name blind mole rats, which belong to the mouse family, show no signs of cancer, even when injected with it. There also is a strand in the mice family that can survive similar treatment as well.

If you think a cancer cannot be passed from one person to another, you only have to look at where it has happened in transplant patients. As Welsh points out, it wasn’t done deliberately and in the very few cases it did occur, the donor was not only in full remission but the cancer was not associated with the transplant organs. Somehow, the donor’s own immunity system kept it under control. Removing the troubled organ did result in a cure for some by the way.

Equally interesting is that cancer tissue can last fifty to sixty times longer than normal tissue before dying. No wonder it makes it harder for the body’s auto-immune system to fight or keep it in check.

Added to this is how the auto-immune system in a woman can not only treat the placenta during pregnancy as off-limits but also the same applies to ectopic pregnancy, those rare occasions when foetal tissue lodges outside the placenta. As Welsh points out, the auto-immune system can also be fooled, they’re just not sure how yet. From my perspective, it looks very much like a Catch 22 situation. If you get your immunity system to recognise even the likes of the placenta as a foreign body to cure a cancer, you also remove any chance of fertility in the long term. Although Welsh doesn’t go that far, there has to be a search through the human genome to see if there is an on/off control for the immunity system to be more efficient.

Don’t think I’m giving all the details here. Welsh covers most of the options for a variety of things that spur on cancers and it can get complicated. He leaves the very serious chemical analysis to the final chapter so much of it is in layman terms for most of us to understand. Just don’t expect it to be straightforward. I did wonder about boosting the immune system but it is less about that and more to do with it recognising there is a problem with the cancerous cells in the first place and I haven’t even touched on mutant cells growing out of control. Welsh also points out some treatments, like anti-oxidants, that have failed.

By the way, something Welsh reminded me of in one chapter is the source of the name ‘vaccine’. Edward Jenner, its discoverer, got the word from the Latin name for the cowpox virus, Vaccinia.

Again, if the length of my review is anything to go by, you can tell this book is an immensely depthy read and I learnt a lot not only about it but seeing some of the bigger picture. I wouldn’t suggest you read it as a means to find a cure for any cancer you, your family or friends might have but it will surely key you into the sorts of research that is currently going on to help the body to help itself. Welsh himself thinks that there will be a breakthrough at some point, although as I pointed out there are several contradictions that would need to be resolved along the way. If you have any interest in the subject at all, then this book will give you some immense insight and also knowledge that humans aren’t the only species that a cancer can get its nasty hooks into.

GF Willmetts

June 2016

(pub: Prometheus Books. 406 page indexed illustrated enlarged paperback. Price: $19.00 (US), $20.00 (CAN). ISBN: 978-1-63388-154-9)

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