From: Alan Kellogg
Location: San Diego, California
Do a search (http://clusty.com works best for this) on the terms "Sticker's Sarcoma" (found in canines) and "Devil Facial Tumor Disease" (DFTD, a condition found in tasmanian devils). The latter is sort of descended from the former, and both are a sort of parasitic pseudo-cancer.
They are, in a word, representatives of a new phylum.
Now think of a new species of parasitic pseudo-cancer. One specific to humans, and which - for some reason - results in the appearance of what might be called a quasi uterus. An organism that functions as a sort of uterus and ovary. One able to produce gametes able to merge with the gametes produced by the host, resulting in a pregnancy. The host gametes produced by a patch of host cells modified by the parasite to perform just such a function. And since an infestation can happen to any sexually mature human, it means males and females can get pregnant. A pregnancy that can occur at any time with no need for sexual activity of any sort.
Think of how it would change society and culture. :)
From: Greg Bear
Hm... kind of a transferrable teratoma! Not implausible, actually. There's all sorts of horror flick ideas in the more desperate angles of biology. Like the wasp that expresses its own endogenous retroviruses to infect and subdue host caterpillars--just the sort of mechanism I was describing in DARWIN'S CHILDREN. Tough to make up stuff with news like this coming in!
Yeah, in reading this post, I was thinking DR right off the bat...
SF gives us the opportunity to look ahead and not be caught with our pants down. However, as the majority think of is as science-fiction, I think the above is an example of something seemingly fantastic to the public that could be used for an action novel, and that would incidentally cue them to the reality of such remarkable circumstance.
From: Alan Kellogg
Location: San Diego CA
Keep in mind that the tumor cells are not the patient's cells. In so far as they can live quasi-independently from their canine or TD ancestor, and take up residence with a different animal (of the right species), living as a parasite, one could consider them unique organisms of a new phylum level life form.
Honestly, since it is not a case of some of the patient's cells changing to become cancerous, one cannot really call them cancers of any kind. What you have is an animal of no discernable body plan colonizing a higher life form, and parasitizing it.
Note that DFTD is fatal. The tumors grow to a size that either closes up the patient's throat or covers the mouth, thus suffocating the devil. After a few weeks Sticker's Sarcoma tends to disappear, and the patient apparently makes a full recovery. However, further tests have been done on some dogs diagnosed with Sticker's Sarcoma, and researchers have found Sticker's Sarcoma cells living on inside the dog quite healthy and happy.
Now, DFTD was first diagnosed in a tasmanian devil in 1996. Thus the causative agent appears to be very young as a species. Sticker's Sarcoma may be as old as 2,500 years. Meaning it has had much more time to adapt to the canine environment. Once past the virulent stage Sticker's Sarcoma appears to pose no real danger to its host. Last I heard, three female tasmanian devils were found who appear to be partially resistent to the DFTD organism, so there might be hope for tasmanian devils.
Here's a question for your biologist friends. Insofar as the DFTD animal is not really descended from the Sticker's Sarcoma animal, can they even be called members of the same phylum?
Remember when evolution behaved itself?
From: Greg Bear
In the case of the Tasmanian devils, the population is highly inbred--which might encourage the spread of similar cancers, evading immune detection. I don't know how much these migrant tumors mix chromosomes with their victims--that is, whether they spread the tumor trait, or simply maintain their genes separately. Biologists?