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Contagious Cancer Found in Dogs 303

Posted by CowboyNeal from the heavy-petting dept.
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."
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Contagious Cancer Found in Dogs More

Contagious Cancer Found in Dogs

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  • Transmitted through sex? (Score:5, Funny)

    by ArcherB ( 796902 ) on Friday August 11, 2006 @10:43AM (#15888991) Journal
    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 (Score:5, Interesting)

      by fredouil ( 891612 ) on Friday August 11, 2006 @10:47AM (#15889020) Homepage
      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 (Score:4, Funny)

        by GweeDo ( 127172 ) on Friday August 11, 2006 @11:35AM (#15889389) Homepage
        But who will eat all the pizza rolls?

    • Re:Transmitted through sex? (Score:4, Funny)

      by MustardMan ( 52102 ) on Friday August 11, 2006 @10:53AM (#15889071)
      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? (Score:4, Funny)

      by krawz ( 662049 ) on Friday August 11, 2006 @11:30AM (#15889354)
      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? (Score:4, Funny)

      by oahazmatt ( 868057 ) on Friday August 11, 2006 @12:50PM (#15889914) Journal
      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."

  • It happens in humans, too. (Score:5, Funny)

    by Skynet ( 37427 ) on Friday August 11, 2006 @10:43AM (#15888994) Homepage
    http://en.wikipedia.org/wiki/HPV#Cancer [wikipedia.org]

    Make sure to use protection, Slashdotters!

    oh wait....

    • Re:It happens in humans, too. (Score:5, Informative)

      by thebdj ( 768618 ) on Friday August 11, 2006 @10:48AM (#15889026) Journal
      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.)
      • Very true, thanks for pointing that out.

        Although at a primitive level, you are getting cancer as a direct result of sexual contact with another person.
      • Carl Zimmer has a great post on this:

        http://scienceblogs.com/loom/2006/08/09/an_old_dog _lives_on_inside_new.php [scienceblogs.com]

        FTP:
        "The scientists propose that several centuries ago, a histiocyte cell in a dog or a wolf turned cancerous. A mutation may have caused the cell to become abnormal--perhaps that LINE-1 element that marks Sticker's sarcoma cells today. But natural selection would have favored other mutations as well that allowed its descendants to become more effective at growing into a tumor. During mating, some

      • Which is why... (Score:5, Informative)

        by jd ( 1658 ) <imipak@ y a hoo.com> on Friday August 11, 2006 @12:54PM (#15889932) Homepage Journal
        ...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... (Score:4, Interesting)

          by RsG ( 809189 ) on Friday August 11, 2006 @02:45PM (#15890650)
          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... (Score:4, Interesting)

          by Reziac ( 43301 ) * on Friday August 11, 2006 @03:21PM (#15890874) Homepage Journal
          [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. (Score:4, Informative)

      by Burlap ( 615181 ) on Friday August 11, 2006 @10:54AM (#15889076)
      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. (Score:5, Informative)

      by eli pabst ( 948845 ) on Friday August 11, 2006 @11:01AM (#15889135)
      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.
    • Make sure to use protection, Slashdotters!

      oh wait....

          Yes, I think you caught the redundancy inherent in that statement, didn't you?

  • Timmy Didn't Kill Old Yeller (Score:3, Funny)

    by Anonymous Coward on Friday August 11, 2006 @10:45AM (#15889006)
    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? (Score:5, Interesting)

    by mochan_s ( 536939 ) on Friday August 11, 2006 @10:47AM (#15889021)
    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? (Score:5, Informative)

      by ComaVN ( 325750 ) on Friday August 11, 2006 @10:50AM (#15889047)
      Regular pathogens did not originate as animal cells
    • Not a doctor, but...

      Presumably the oddity is that it's a cancer that behaves as a pathogen--that is, these are rogue dog cells that can jump from dog to dog and continue reproducing as a tumor. 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 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.
      • 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... (Score:4, Insightful)

      by brunes69 ( 86786 ) <`gro.daetsriek' `ta' `todhsals'> on Friday August 11, 2006 @10:56AM (#15889098)
      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... (Score:4, Insightful)

        by CastrTroy ( 595695 ) on Friday August 11, 2006 @11:10AM (#15889217)
        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... (Score:4, Informative)

        by Ford Prefect ( 8777 ) on Friday August 11, 2006 @11:16AM (#15889258) Homepage
        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.
      • 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.

        Actually, the human body attacks cancers with an amazing speed and dedication. That's why when you get an immune suppressive disease like HIV, GRID or Hep C, you start getting all these weird cancers that nobody ever gets. The most common in the case of AIDS patients is Kaposi's Sarcoma, which is caused by a strain of herpes that we all have (HHV-8,) because once our natur
    • That's a very interesting point. How do you label this? It's not a virus, or it would infect healthy cells of the host. It doesn't appear to be bacterial. It's not really a cancer, since cancer is a part of the host's own cells. What is it?

      It *behaves* most like a bacterial infection, but it causes tumors. Or rather, it pauses in a host and somehow replicates itself in large quantities, which is mistaken for a cancerous tumor. How does it feed?

      This is a very interesting biological concept.

      • simple (Score:2)

        by r00t ( 33219 )
        It's a dog infection. Dogs can get infected by dogs.

        If you prefer to be less specific, it's an animal infection. The dogs get infected by animal cells.

      • How does it feed?

        Probably the same way as any "normal" cancer: it gets supplied with nutrients and oxygen from the blood stream, just like all the rest of the dog's cells.

    • 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
    • It's not a tumor...
    • 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

  • Not Taz!! (Score:5, Funny)

    by Rob T Firefly ( 844560 ) on Friday August 11, 2006 @10:48AM (#15889023) Homepage Journal
    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 (Score:3, Interesting)

    by mobby_6kl ( 668092 ) on Friday August 11, 2006 @10:49AM (#15889040)
    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. (Score:5, Interesting)

    by ip_freely_2000 ( 577249 ) on Friday August 11, 2006 @10:50AM (#15889045)
    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. (Score:4, Insightful)

      by SlashSquatch ( 928150 ) on Friday August 11, 2006 @11:21AM (#15889289) Homepage
      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! (Score:5, Funny)

        by Valdrax ( 32670 ) on Friday August 11, 2006 @04:28PM (#15891336)
        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!
    • The key, I've found, is to enjoy the company of what ever animal or person you love while they are still with us. Some things we can't control. Life happens and part of life is death. Take lots of pictures and enjoy the time you've been given. Lamenting what could have been produces only poisoness fruit for the soul and the mind.

      Love. In the end, it's all you can do to honor someone close to you.

    • Re:Damn...I just lost my dog to cancer. (Score:2, Informative)

      by Anonymous Coward
      Probably not the cause. From the article: "Sticker's sarcoma is usually not fatal . . .".
    • 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.

      Sorry to hear about your dog.
      As much as it sucks to lose a pet, I'm sure she would have preferred a shorter, fun and happy life to being bored and cooped up inside all day.
      Besides, there's no indication that i
    • I'm sorry to hear about your dog, but don't beat yourself up about it, or let this deter you from taking future dogs to the park to socialize.

      The transmissible cancer described in the article sounds like a very specific, sexually transmitted illness.

      Anyway, dog parks aren't doggy sexual playgrounds. Most specifically ban she doggies in heat, and I don't think play-humping would do the trick.
  • I believe it was John Carpenter's masterpiece, The Thing. Dog eats alien, dog transforms into bloated mass of cells, Thing eats humans.

  • Cancer clusters... (Score:2, Interesting)

    by Varka ( 767489 )
    Perhaps this will turn out to be a partial explanation for the "cancer clusters" you read about every now and then. Varka
    • Perhaps this will turn out to be a partial explanation for the "cancer clusters" you read about every now and then.

      If, and only if, the occupants of these clusters turn out to be vampires.

  • It's not even really LIKE a normal cancer... (Score:5, Informative)

    by ScentCone ( 795499 ) on Friday August 11, 2006 @10:54AM (#15889084)
    ... 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.
    • 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.
      • Yes and no. I think the more interesting discovery is that there's a species of creature who's anscestry includes a highly evolved creature (dog) and yet is on-par in terms of lifecycle with some of the least complex (colonial microbes). This might cause us to re-think much of what we believe to be true about the evolution of simple species, which might well have gone through this reversion to single-cellular life form multiple times.

        Then again, this might be rare enough that it has had little impact on the
    • There's nothing worse than anthropomorphizing your description of cellular mechanics.

      I'll take hyperbole for $1,000, Alex.

    • 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.
      • 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.

        It's a question of degree of complexity. There simply isn't enough processing horsepower in a single cell to provide the framework for what we comfortably refer to as a mind. So, I would actually would "raise an eyebrow" is someone attributed cognition and volition to a strand of DNA, but have no trouble assigning "mind" cap
    • ...There's nothing worse than anthropomorphizing your description of cellular mechanics.
      Well, maybe cancer. Infectious cancer might also be worse.
      Or having your leg chewed off by a wolverine.
      Oh, oh, kidney stones, I hear they're a lot worse than anthropomorphizing your description of cellular mechanics.
      And don't forget about ...

    • Re:It's not even really LIKE a normal cancer... (Score:4, Funny)

      by Kelson ( 129150 ) * on Friday August 11, 2006 @01:41PM (#15890221) Homepage Journal
      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? (Score:3, Interesting)

    by neatfoote ( 951656 ) on Friday August 11, 2006 @10:55AM (#15889091)
    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? (Score:2, Interesting)

      by Anonymous Coward
      Nice comment. You hit the nail of why this has made immunologists (and the general medical research community) very excited. It's a naturally occuring neoplastic growth that is 'non-self' but not recognised as such by the host immune system. Thus it either is able to mimic the host tissue and/or completely evade the immune system. Study of this and the tassie devil tumours may provide novel insights into ways to enable transplanted organs or cells to evade the host immune system. From diabetes to heart
      • Far more likely that one of our fellow idiots will figure out some way to use this new discovery to kill us all.
    • If this is something unique among cancers, then maybe it's possible to find the mechanism that these foriegn cells are able to integrate themselves in another genetically different organism. Once that could be discovered, maybe this would lead to other approaches in combatting more typical forms of the disease. (I'm not in any medical field, but I've never heard of cancer cells acting like a parasite like these seem to do.)

      After just recently losing someone close to cancer, it'd be nice to see some earth-sh

    • Re:How does it evade the immune system? (Score:4, Informative)

      by lockefire ( 691775 ) on Friday August 11, 2006 @11:39AM (#15889426)
      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... (Score:5, Interesting)

    by aapold ( 753705 ) on Friday August 11, 2006 @10:55AM (#15889095) Homepage Journal
    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... (Score:4, Funny)

    by toxcspdrmn ( 471013 ) on Friday August 11, 2006 @10:56AM (#15889101) Homepage
    ...not to lick your dog's backside.
  • Weird..... these cancer cells have evolved an ability not only to metastasized to different parts of a dog's body but to other dogs too. At this point I really don't think we should call them cancer cells anymore..... they are a new type of free living organism.... like a parasite. I wonder why they are restricted to only infecting other dogs? Does interspecies transmission produce too much of an immune response in a different host?

  • confusing (Score:4, Interesting)

    by i_should_be_working ( 720372 ) on Friday August 11, 2006 @10:59AM (#15889124)
    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)?
    • Well, if you repaired whatever damage occurred to turn the cells cancerous you could recover the original dog!

      Try doing that with bacteria.

      (I Am Not A Biologist, so this is quite likely a stupid idea)

    • 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)?

      The alien thing is a dog cell, not a bacterium or a virus or a protozoan or a prion or a parasite. It is an infectious disease, yes, but a different variety. If a doctor exclaims, eureka, malaria is caused by a protozoan and not bacterium, and you respond, "well, same difference," then you should stop reading general interest healt

  • spread the word (Score:3, Funny)

    by Mantooth ( 991503 ) on Friday August 11, 2006 @10:59AM (#15889125)
    teach your kids the dangers of red rocket

  • If this spreads to cats... (Score:3, Funny)

    by Iphtashu Fitz ( 263795 ) on Friday August 11, 2006 @11:01AM (#15889139)
    ...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 (Score:5, Informative)

    by mapkinase ( 958129 ) on Friday August 11, 2006 @11:06AM (#15889167) Homepage Journal
    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.
    • 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.
    • Its not.
      Its not even deadly, as most dogs immune system will be able to supress the infection in a matter of months.
      Those "external tumor infections" have all the weaknesses of living cells without the protection a normal cancer cell has by being hard to distinguish from "good" cells. (while prions are just a pain in the ass to kill)

  • We did a survey (Score:4, Funny)

    by Rik Sweeney ( 471717 ) on Friday August 11, 2006 @11:14AM (#15889239) Homepage
    The dogs said that it was a "Ruff" deal...

    The Tasmanian Devils just spun around quickly, said something completely incomprehensible and blew a rasberry...
  • These tumor cells will grow in any dog. It would be interesting to see if they will infect closely related species. Will they grow in wolves, coyotes, jackals, etc.? Are there any breeds of dogs which are immune to these tumor cells? Will they grow in prey bitten by a dog, such as rabbits? One possible use for these tumor cells could be to determine how closely other species are related to dogs.

    ----------------
    Steve Stites

  • Some Informative Links (Score:3, Informative)

    by JoshDM ( 741866 ) on Friday August 11, 2006 @11:25AM (#15889310) Homepage Journal

    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.

  • which is single-celled, asexual and an obligate parasite of dogs.
  • What happens when one of those weirdo ladies "accidentally falls asleep" on her couch and wakes up to her [infected] dog licking her? [thestranger.com] Is it contained to dogs, or do we have the next human version of cancer on our hands?
  • Contagious cancer? As if I didn't have a million reasons to stay a pasty, game-addicted, furtive and nervous agoraphobe. If it can happen to our canine brothers, it can happen to us.

  • Doggie Cancer Kills (Score:2, Interesting)

    by blooba ( 792259 )
    I borrowed my nickname "blooba" from my late dog. I lost him to cancer last year. I spent $10,000 trying to treat his mast cell tumors, and I think I gave him a few extra months of comfortable living before the fucking cancer metastisized like a fucking wildfire. Anyway the point I'm trying to make is that it wasn't until after I put him down that his team of highly trained veterinarian oncologists at Manhattan's most prestigous Animal Cancer Treatment Center told me that canine cancer has a 100% mortali

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