Two Naked Mole Rats, Seemingly Immune to Cancer, Got Cancer | Hacker News Reader

Two Naked Mole Rats, Seemingly Immune to Cancer, Got Cancer

nytimes.com

63 pointsdkarapetyan21 comments

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Bear in mind that researchers have colonies of thousands of these animals, and in all the time people have been looking, only a tiny number of cases of cancer have been cataloged in this species. [1] Compare that with the cancer incidence and mortality rates in other mammals.

The present thinking on various mole rat breeds and their cancer resistance is that they have more active and more useful cancer suppression gene activities for p16, p21, p27, ARF, etc, and that their tissues have a lot more high molecular weight hyaluronan than peer species [2]. Disabling the gene producing the hyaluronan makes them vulnerable to cancer, and that appears connected to p16 activity.

The important outcome of the particular setup for naked mole rat biochemistry may be that their cells are a lot more sensitive to crowding, and will more readily self-destruct when that happens. Without that, cancer is more easily induced.

[1]: http://dx.doi.org/10.1177/0300985816630796

[2]: http://www.rochester.edu/news/show.php?id=6572

Is "crowding" a common state for tissue to get into? Polyploid plant tissue comes to mind.

> Dr. Delaney and her colleagues have studied lesions on naked mole rats for more than a decade [...]

One of the wonders of science is the important discoveries that come from a focused investigation into some of the most obscure things.

When we find people who are both talented and dedicated enough to focus on such a specific realm of science, we really ought to have plenty of money and resources for them.

I suspect we can be doing a lot better, but I doubt this is the worst of all the parallel universes when it comes to supporting science.

There's a decent chance they were studying other things as well, at the same time.

> Three months later they found no remnants of the cancer, making him the first known naked mole rat cancer survivor.

Did it magically cure itself? Does that ever happen in humans when there is no medical intervention? That seems amazing.

The body is fairly good at fighting off illnesses and disease. Not a doctor, but from what I have read often by the time someone is diagnosed with cancer it has progressed to a stage where the body's immune system has failed to fight it off, so it is probably rare for cancer to go away on its own. Here is one article suggesting that cancer can go away on its own: http://articles.mercola.com/sites/articles/archive/2008/12/1...

>> so it is probably rare for cancer to go away on its own.

It is actually very common. It has happened to you many times without you knowing it. Cancerous cells can appear and be taken care of immediately by various natural mechanisms. There are mechanisms to correct errors in DNA before a cell divides, or a damaged cells can self-destruct. This happens all the time as skin cells deal with DNA damaged by UV light. And there are diseases that cause cancer not directly but because of breakdowns in these repair mechanisms (see DNA repair-deficiency disorder). If you looked at every cell in your body no doubt a great many are technically cancerous at any one time. A clinical case starts when the natural mechanisms fail and damaged cells divide enough to cause the disease we call cancer.

The distinction is medically important because if you go looking for every tiny little bit of cancer you will find a great many that would never give rise to a clinical case, that would never impact the patient.

Have you looked into what combination of mutation rates and number of required mutations would be necessary for your model to work? Usually people say it is something like 10^-8 per bp per division and you need to collect 3-6 mutations to get cancer.

Isn't cancer predicated on mutations that result in uncontrolled cell growth? I imagine there are a great many mutations that result in cell death or an inability to properly divide. Those mutations wouldn't contribute to cancer risk. So maybe you need 3-6 but only amongst those bits of DNA that actually matter.

Yes, that is correct. It would only be some "special" combinations of mutations, not just any set.

Just FYI, Mercola is really not a good source to link to for anything. For instance, he thinks mobile phone radiation causes cancer and peddles anti-vax messages. Can't comment on the specifics of that article, but wikipedia does point out:

> Phyllis Entis, a microbiologist and food safety expert, highlighted Mercola.com as an example of websites "likely to mislead consumers by offering one-sided, incomplete, inaccurate, or misleading information."

Some more sources:

[1] https://www.quackwatch.org/11Ind/mercola.html [2] https://en.wikipedia.org/wiki/Joseph_Mercola [3] https://sciencebasedmedicine.org/9-reasons-to-completely-ign... [4] http://www.chicagomag.com/Chicago-Magazine/February-2012/Dr-... [5] http://www.alternet.org/personal-health/four-biggest-quacks-...

Spontaneous remissions have been observed, and aren't really well understood, as far as I know. In this case, though, they had removed the "dark red and purple mass" of the original tumor, and the rat was a "survivor" since no overlooked bits of tumor or metastases turned up afterwards. For all that oncology is a deep and sophisticated branch of medicine, "just take it out" is still sometimes a good strategy.

Yes, there are many cases where the body's immune system can completely cure a modest cancer infection. I believe the common term used by doctors is "the tumor magically melted away". However, if the immune system leaves just 2-3 tumor cells left that are not targeted, they can grow back into a full tumor.

Also, the whole affair can result in heavy auto-immune diseases, as the targeted cells descend from healthy organ cell types.

Can you explain pls?

When the immune system learns to destroy cells, it also remembers the markers for bad cells. If you have (for example) cancerous liver cells and your immune system learns to destroy these, the potential exists for it to learn markers that are also present on normal liver cells.

After your cancer is gone, this memory that partially (or entirely) applies to regular cells will lead to your immune system trying to destroy normal, healthy cells.

Thank you for your reply.

Has this ever been theorised as a cause for athritis?

What is the immunity to a cancer supposed to mean? Immunity to a random mutation in a cell's DNA?

I don't think so - I think it means the ability to destroy, or otherwise render harmless, those mutations that behave in a cancer-forming way.

The cell looks like normal one, perfectly legitimate, it just divide and divide..

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