Contagious Cancer Found in Dogs

Dan East writes "Scientists in England have gathered definitive evidence that a kind of cancer in dogs, known as Sticker's sarcoma, is contagious. It is spread by tumor cells getting passed from dog to dog through sex or from animals biting or licking each other. Robin Weiss and his colleagues did genetic studies on the tumor cells from 40 dogs with Sticker's sarcoma, collected from five continents, which showed that all the tumor cells are clones of each other. The parent cell probably arose in a domesticated dog of Asian origin — perhaps a husky — hundreds of years ago, and perhaps more than 1,000 years ago. A similarly transmissible cancer has recently been discovered spreading through populations of Tasmanian devils."

Transmitted through sex?

[ArcherB (796902)]

Great! Now I have to give my dogs a talking-to about using protection before they go to the doggie park!

I wonder if they will start having puppy prophylactics in a candy dish at pet-smart.

tasmanian devil & spreading cancer

[fredouil (891612)]

unfortunately this kind of cancer is not new, here in Australia, the Tasmanian devil are diying and will soon disapear. http://news.nationalgeographic.com/news/2006/02/02 27_060227_tasmanian.html [nationalgeographic.com]

Re:tasmanian devil & spreading cancer

[RsG (809189)]

I dislike the arguement that "nature" has any intent or say in the matter. It's too close to a religious belief for my liking; making the natural world or the proccess of evolution into some planning, thinking deity.

Evolution is non-linear. It's a blind proccess based on probability, not some infallable mechanism for ensuring the correct changes occur. Extinction is not fated, nor does it unerringly take only those species who are unsuited to their environment (look at the major mass extinctions in history as proof of this).

And even when natural selection is responsible, why is that "right"? Evolution has no ethics, it simply is. Moreover, even if we start from the assumption that natural selection is right (or is best not interfered with), how can we seperate it out from every other factor involved in an extinction? Death by evolution is like death from old age; it's not a specific cause, it's a general description of what went wrong.

The death of the dodo or the passanger pigeon can argueably be considered a form of evolution; those species unable to cope with a new predator (man) die off. Yet we restrain ourselves from causing other species to go extinct.

We are ourselves unnatural creatures. The natural state of humans is poor health, early death, superstitious ignorance and starvation. We're hunter-gatherers naturally. Do we view our deviation from evolution as wrong?

And even if the tasmanian devils are dying out purely due to non-human factors, what arguement is there against trying to preserve them?

If you want to argue that the only species we have an obligation to preserve are the ones that our own actions have endangered, then that's fine - you're entitled to your own point of view. However, I don't agree with that line of thinking. The fact that we're probably blameless in the fate of the tasmanian devil doesn't mean we have no cause to preserve them.

Re:tasmanian devil & spreading cancer

[deuterium (96874)]

There's no right or wrong, just an outcome.

Ahh... a coward after my own heart. I've labored on many occasions to illustrate the fact that whatever people do, it is literally natural. To assume anything else would be placing us in the realm of (again, literally) the supernatural. So whether we destroy the planet, live in wigwams, colonize Mars, or genetically engineer a mouse that glows in the dark, the result is no more unnatural than a beaver damming up a culvert. There is no grand evolultionary, Gaia-mind plan that we run the risk of mucking up. The laws of nature simply play themselves out wordlessly and aimlessly. Isn't that comforting?

Re:Transmitted through sex?

[MustardMan (52102)]

Man, am I glad I had my dog's balls chopped off. Nearly all of his humping instinct is now gone... we might have dodged a bullet!

Re:Transmitted through sex?

[gstoddart (321705)]

Christ, it's hard enough to get them to take their vitamins. Putting one of those on 'em is gonna be a pain.

"Hold on, boy, there's an air bubble."

Well, by the time you work out the air-bubble, he might just want a smoke and a cuddle. Then you won't have to worry about him humping strange dogs. :-P

Cheers

It happens in humans, too.

[Skynet (37427)]

http://en.wikipedia.org/wiki/HPV#Cancer [wikipedia.org]

Make sure to use protection, Slashdotters!

oh wait....

Re:It happens in humans, too.

[thebdj (768618)]

There is a big difference. In the HPV case, there is a viral infection THAT MAY cause cancer in people with the virus. This is talking about the tumor cells actually transferring from one animal to another to cause infection. So to recap, HPV is a virus that may cause cancer in women with it and should not be confused with communicable cancer. A communicable cancer would be transferred from person one to person two and cause a cancer infection. (You know, how the flu, common cold, and a host of other diseases work.)

Which is why...

[jd (1658)]

...the cancer cells are identical. Not merely "similar", in that they're cells of cancer type X, but a direct copy of the original cancer. (The genes that are present are from a husky, if I understand the story correctly, and the markers are clear enough to be able to estimate a timeframe. This is how they know the origin, as opposed to finding said husky in a glacier somewhere.)

This story has a lot of implications that aren't necessarily obvious. First, if both dogs and marsupials can have a contageous, directly-transmissable cancer, then so can any species, through ANY mechanism that involves a transfer of cells. I wonder if blood banks are being screened for such cancers. Given the total lack of speed they showed over AIDS or vCJD, I seriously doubt they've got any serious monitoring in place for such pathogens. (Sure, it's a theoretical, but it would seem better to KEEP it a theoretical, rather than wait until it's a major problem.)

Since this was presumably two different spontaneous mutations, transmissable cancer must be capable of arising in almost any organism at almost any time. I doubt there would be many carcinogens in common between Alaska and Australia, despite them having the same first and last letters. Understanding that mechanism would seem very important, as it would seem reasonable to assume that anything that easy to start would be equally easy to stop.

Finally, for the cancer to spread in the way described, we must be talking about cells with a high degree of mobility. This can't be something attached to something, like a tumour, or it couldn't spread identically from organism to organism. It must also be fragile enough that an airborne version has not yet evolved. However, that may be merely a matter of time. I think medical labs should be putting the effort into understanding the mechanisms and the limitations of transmissable cancers, as we really don't want to be in the usual mess of playing catch-up afterwards, but don't need to do more than necessary if research shows that the limitations are barrier enough.

Re:It happens in humans, too.

[Burlap (615181)]

close, but not quite.

Human Papolova Virus (HPV) can be transmitted from person to person, however the cancer cells it creates are from the host. The article states that in this case the very cancer cells themselves are being transmitted and growing in a new host. These tumors have no genitic relation to host, whereas HPV induced cancers do.

Re:It happens in humans, too.

[eli pabst (948845)]

I haven't read the journal article in Cell yet, but from my understanding this isn't interesting from the standpoint of a virus being able to transform normal cells into a tumor. There are a large number of examples of that (EBV, KSHV, hepatitis B virus). This is interesting because it's the actual tumor cells themselves that are being transmitted from one host to another. You can do that in the lab by injecting tumor cells from one mouse into another and letting a new tumor form, however I haven't seen examples of this occuring naturally and in those experiments the mice need to either be from the same genetic background or immunosuppressed SCID mice.

How are these Cancer Cells?

[mochan_s (536939)]

It is spread by tumor cells getting passed from dog to dog through sex or from animals biting or licking each other. Robin Weiss and his colleagues did genetic studies on the tumor cells from 40 dogs with Sticker's sarcoma, collected from five continents, which showed that all the tumor cells are clones of each other.

So, all tumor cells are clones of each other and not related to the dog. How is this cancer? Isn't it just a regular pathogen then?

Re:How are these Cancer Cells?

[ComaVN (325750)]

Regular pathogens did not originate as animal cells

For that matter...

[brunes69 (86786)]

For that matter, how the hell are these foreign cells growing **whole tumours** in the host without the host's immune system going into complete overdrive?

I mean, it's hard to even transplant a finger in a human without using huge amounts of anti-rejection drugs. How is there a tumor growing inside the dog, with cells that must have a totally different DNA and chromosone pattern? Why is the dog's host system not attacking it?

I mean, part of the whole problem with cancer is that the cells are in fact your own cells, so your body never attacks the infection. But if the cancer is directly contagious than this is not the case at all.

Re:For that matter...

[CastrTroy (595695)]

I think it has something to do with how close the cells are to the cells of the host. In the case of cancer cells, they contained somewhat damaged DNA, which is the cause of the tumour, yet your body still doesn't attack it, because for some reason or another it doesn't see it as a threat. I think the same thing would apply here. Remember that all breeds of dogs are the same species, even though there's a wide variation of DNA out there to account for all the different breeds. Perhaps dogs have a much larger margin which their body considers safe for presence in their own body due to such a large variation in the genes present in the species.

Re:How are these Cancer Cells?

[NearlyHeadless (110901)]

It's closest, really, to a parasite, but it's still weirder than that, since it's genetically the same species as its host.

It's genetically almost identical, but I think we can say this is a new species. It's thus a single-cell species of dog.

Not Taz!!

[Rob T Firefly (844560)]

A similarly transmissible cancer has recently been discovered spreading through populations of Tasmanian devils.

Symptoms include dizziness, slurred speech, and violence toward woodland creatures... especially rabbits.

Damn...I just lost my dog to cancer.

[ip_freely_2000 (577249)]

A 9 year old Border Collie with an aggressive tumor in her front leg. This happened two weeks ago. She spent a lot of time playing with other dogs in the park. I'd hate to think that me wanting my dog to have some fun is what killed her. I'd hate to have to wonder and worry about this with my next dog.

Ssshhhh!

[Valdrax (32670)]

2. I'd choose bark park with a 3/4 life span vs. no fun for a long time and all the other dogs I know agree.

Sshhh! Sshh! What are you doing? On the internet, no one's supposed to know that you're a dog!

It's not even really LIKE a normal cancer...

[ScentCone (795499)]

... in the sense that these are not the dogs' own cells. This is much more like the dog being a petri dish for a parasitic cell that's being physically passed along, almost like bacteria. The cells just set up shop in the new dog's tissues.

Slightly annoying, in TFA, is the notion that "DNA will try anything to reproduce itself." That might want to read more like "just about everything happens to DNA as it's cloned, and sometimes the mutations work better, and sometimes they fail." There's nothing worse than anthropomorphizing your description of cellular mechanics.

Tasmanian Devils have it worse...

[aapold (753705)]

Tasmanian Devils are being wiped out by a transmissable cancer called Devil Facial Tumor Disease [wikipedia.org], its a pretty hideous disease that eventually causes the animals to starve to death as they are unable to eat. It is transmitted when Tasmanian Devils fight each other. It is estimated 100% fatal within 12-18 months, it is estimated that over half of all remaining Tasmanian Devils in the wild have it, and it has decimated their population.

In case you needed another reason...

[toxcspdrmn (471013)]

...not to lick your dog's backside.

confusing

[i_should_be_working (720372)]

FTA:
A cancer cell is usually an animal's or person's own cell..

..the cells are not genetically related to the dogs they are in -- proof that they did not arise from the dogs' own cells.

..all the tumor cells, no matter where they were collected, are clones of each other.

If every cell of this cancer is a clone, and not the dog's own cells screwing up, then I'd say this is more like an infection. An alien organism has invaded the dog's body and then replicates. What's the difference (in terms of the vector) between this and a bacterial infection (also single-celled)?

Original peer-reviewed Cell link

[mapkinase (958129)]

In this table of contents [cell.com] go to "Clonal Origin and Evolution of a Transmissible Cancer". Summary:

The transmissible agent causing canine transmissible venereal tumor (CTVT) is thought to be the tumor cell itself. To test this hypothesis, we analyzed genetic markers including major histocompatibility (MHC) genes, microsatellites, and mitochondrial DNA (mtDNA) in naturally occurring tumors and matched blood samples. In each case, the tumor is genetically distinct from its host. Moreover, tumors collected from 40 dogs in 5 continents are derived from a single neoplastic clone that has diverged into two subclades. Phylogenetic analyses indicate that CTVT most likely originated from a wolf or an East Asian breed of dog between 200 and 2500 years ago. Although CTVT is highly aneuploid, it has a remarkably stable genotype. During progressive growth, CTVT downmodulates MHC antigen expression. Our findings have implications for understanding genome instability in cancer, natural transplantation of allografts, and the capacity of a somatic cell to evolve into a transmissible parasite.

This is just great. This is worse that prions.

Re:Kill all the dogs!

[k3vlar (979024)]

I see that you have never owned a cat or dog. It can be a very rewarding experience, caring for something like that.

Having said that, I agree with your views about how some people seem to value the lives of animals over other human beings.
I saw a commercial once that truly sickened me. They were asking for donations to help save captive bears in an empoverished third world country! I couldn't believe that someone could ask for money to save bears, instead of helping the PEOPLE that couldn't afford enough food. The bears were being held captive to be put on display to earn donations from passers-by, and I thought, "How stupid can this donation organization be! Solve the people problem, and you also solve the bear problem!"

Animal rights groups sicken me sometimes.