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

[GweeDo (127172)]

But who will eat all the pizza rolls?

Re:tasmanian devil & spreading cancer

[by Anonymous Coward]

Here's a question: is it right for us to stop it? This appears to be a natural weakness of Tasmanian devils.

Humans aren't above evolution. We're part of the process. And one thing evolution has given some of our species is empathy. Another is to determine a system of values to live our lives by. If enough of us determine that the "right thing to do" is to save the Tassie Devil because we're concerned about their plight, then evolution has seen fit to give the Tassie Devil a leg up. There's no right or wrong, just an outcome.

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: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: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?

[krawz (662049)]

Hopefully the people at PetSmart will handle the...application...of the aforementioned 'protection', because I know I'm not. Imagine the Want Ad... PetSmart, Inc is now seeking a full-time Canine Fornication Specialist. 1+ year(s) previous CFS experience preferred. Dust off your rubber glove and drop off your application today!

Re:Transmitted through sex?

[oahazmatt (868057)]

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

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."

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:Which is why...

[RsG (809189)]

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.

I could be way out of line here, but I'm pretty sure that metasticized cancer cells have a high degree of mobility in normal, non-contagious cancers. The ability to jump from one organ to another via bodily fluids doesn't seem that far removed from the ability to jump from one organism to another via those same fluids. So I don't think the distinction here is mobility.

Part of what's unusual about this strain of cancer is mentioned in TFA:

Studies suggest that, unlike most tumor cells, which contribute to their own demise by becoming increasingly genetically fragile, Sticker's tumor cells are remarkably genetically stable, perhaps explaining in part their evolutionary success.

So the cells are unusual, at least when compared to other forms of cancer.

Another thing I find odd is that the dog's immune system doesn't recognize these cells as foreign and attack them; one of the reasons that your own immune system has trouble attacking your own cancer cells is because they're identical to the host's. OTOH, they say the cancer isn't fatal in dogs, so it's quite possible that the immune system does limit it's development.

Re:Which is why...

[Reziac (43301)]

[Hat: I am a professional dog trainer and breeder with 37 years experience.]

I first noticed an apparently-contagious tumour in dogs about 15 years ago. Transmission seems to require direct contact (not necessarily venereal), and the growth is always located in or just under the skin. Superficially, it resembles an ordinary fatty tumour. Under the microscope it looks like it's not exactly benign, but not like a "hot" cancer either. I've never seen one develop into anything serious.

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.

Timmy Didn't Kill Old Yeller

[by Anonymous Coward]

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.

Tonight, President Bush will go on TV and address the nation saying that recent research has shown that China & North Korea used biological weapons on the United States and its best friends. This will be justification for the preemptive nuclear attacks the United States has planned next week. He's got a real good feeling about this one. It's a slam dunk.

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

Re:How are these Cancer Cells?

[LurkerXXX (667952)]

It's a parasite. The strange thing is their claim that after dog bites these "cancer cells clog up the jaw, and the poor animals die of starvation".

I can see how a parasite like this might get a free ride in the genital tract, but in the case if bites like this, the host dog's immune system should recognize these 'cancer' cells as foreign material and destroy them.

Re:How are these Cancer Cells?

[Graff (532189)]

The strange thing is their claim that after dog bites these "cancer cells clog up the jaw, and the poor animals die of starvation".

That's the cancer that affects tasmanian devils, not not the cancer that is affecting dogs. The dog version apparently is very rarely fatal to the dogs that contract it.

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:For that matter...

[Ford Prefect (8777)]

From the article linked from elsewhere in the comments [scienceblogs.com]:

The scientists found that the Sticker sarcoma cells make very few of the surface proteins that vertebrates use to distinguish self from non-self. It appears that the tumor cells can avoid an all-out attack from the immune system. Instead, the immune system reins in the cancer cells, which can survive in the dogs even after their tumor disappears.

It's ... evolved.

Re:How are these Cancer Cells?

[rabbitfood (586031)]

They are related to the dog simply because they are dog cells (and most dogs are genetically very similar), they just happen to be cancerous, transmissible and genetically identical dog cells. Tumour cells are usually aberrant (mutant) cells from the host animal that don't differentiate (i.e. turn into the right sort of cells for the tissue they are in) and don't regulate their division (i.e. they multiply without restraint). That's what makes them cancerous. And because most of them don't look anything spe

Re:How are these Cancer Cells?

[Red Flayer (890720)]

FTFA:

"I rather thought we might disprove this, but it came out the other way around," said Robin Weiss, of University College London, who led the study appearing in today's issue of the journal Cell. "It is clearly a dog tumor cell behaving absolutely like a parasite." Weiss called the tumor transmission trick "a curiosity of nature."

This isn't the first time that a communicable parasite has evolved from a host's own cells and/or cell contents. Prions [microbe.org], such as the ones thought to cause BSE, are another i

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.

Your dog wants a condom

[mobby_6kl (668092)]

getting passed from dog to dog through sex ... or licking each other.

And it doesn't seem that human to human cancer transmission is impossible, too. This could be the next big thing once we've cured AIDS.

How common is Sticker's sarcoma, though? We have a dog, and although she's not getting to fuck like a rabbit, dogs often lick each other and sometimes bite.

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.

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

[SlashSquatch (928150)]

Condolences.

About the bark park, your dog would not have had it any other way.

Don't worry because:

1. Even though you may point to a risky behavior, this does not imply a cause - effect relationship. Many cancer causing agents will always abound in our environment.

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.

3. A good chunk of the dog population gets the shaft, stuck on a chain, or in a cage and possibly gassed in their prime.

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.

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

[axolotl_farmer (465996)]

The cancer cells are mutated dog cells, only that they originated in another dog maybe 1000 years ago. The new discovery is that the cancer cells can infect other dogs. Usually, cells from another individual (even cancerous cells), are recognized as foreign and destroyed by the immune system.

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

[digitalhermit (113459)]

There's nothing worse than anthropomorphizing your description of cellular mechanics.

Interesting sentiment... Funny how we can talk of "mind" as opposed to "brain" and nobody raises an eyebrow. The idea of consciousness is not that far removed from the idea that DNA is selecting host animals. After all, what is consciousness but the expression of chemical and electrical processes in the brain, similar to the chemical and electrical processes in DNA replication.

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

[Kelson (129150)]

There's nothing worse than anthropomorphizing your description of cellular mechanics.

So true. DNA hates it when you do that.

How does it evade the immune system?

[neatfoote (951656)]

My understanding was that normal cancers survive in the body because they're part of its own tissue, and are recognized by the immune system as normal body cells. If, as the article says, this sarcoma really is transmitted via the cancer cells themselves (as opposed to an infectious cancer-causing agent like a virus), then shouldn't the infected dog's immune system recognize the cells as coming from another dog and attack them?

Re:How does it evade the immune system?

[lockefire (691775)]

From the original article in Cell:

A recent study (Hsiao et al., 2004) shows that, during progressive growth, secretion of TGF-b1 by CTVT acts as a potent local inhibitor of host immune responses, as does the downmodulation of DLA class I and II expression observed by us and others (Cohen et al., 1984).

DLA is basically the dog immune system method of identifying 'self'. These tumor cells are hiding the fact that they are not-'self' well enough that they easily overwhelm any immune response.

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)?

spread the word

[Mantooth (991503)]

teach your kids the dangers of red rocket

If this spreads to cats...

[Iphtashu Fitz (263795)]

...then I'm leaving the planet. This was all predicted in the original Planet of the Apes [imdb.com] movies...

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:Original peer-reviewed Cell link

[stevesliva (648202)]

This is worse than prions.

I don't think so. You can quarantine this, and stay away. With prions, you never see them coming. And then your brain melts.

We did a survey

[Rik Sweeney (471717)]

The dogs said that it was a "Ruff" deal...

The Tasmanian Devils just spun around quickly, said something completely incomprehensible and blew a rasberry...

Some Informative Links

[JoshDM (741866)]

A Readable Technical Discussion of Stickers Sarcoma [scienceblogs.com] and Canine TVT - 2004 to Congress [vin.com].

Excerpt on Geographical Distribution from the latter: TVT is seldom or no more detected in North and Central Europe and in North America, mainly due to the population control of stray animals, the preventive pre-breeding examination and the effective treatment of clinical cases. With a few exceptions, TVT remains endemic in the rest of the world, obviously because of the uncontrolled population of stray dogs and the inadequacies of exerting effective treatments.

The Punnic Wars, Part 2

[krell (896769)]

"We had a chance with aids, but we blew it."

You can say that again.

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.