Transplanting Tumors (February 7, 2014)

Today’s most excellent article by the most excellent Cecil: [Can tumors be transplanted?](Can tumors be transplanted?)

My pedantic observation: The questioner asks about transplanting cancerous tumors. Cecil answers in the affirmative, and completely on-topic with several fascinating citations and examples. (We would expect no less.)

But the title is misleading. “Tumor” is not necessarily “cancerous tumor”:

I don’t know if anyone else would notice the distinction, or even would pay too much attention to the literal content of the title (and its discrepancy with the text), but I might humbly and most diffidently suggest tweaking the title to focus on cancer. Which is really the point of the question-and-answer. Otherwise, the other natural question and answer (“Can you transplant a benign tumor?” “Why yes, and probably nothing bad will ever happen”) is just lying there like a dead rat in the wall.

The bit I was wondering about is that all of the cases Cecil talks about involve deliberate organ or tissue transplant, where the recipient will be getting anti-rejection drugs. More interesting, I think, is the question of whether a foreign cancer can take hold in a host body without the benefit of anti-rejection drugs.

The cells of tumors can transfer from one animal to another, Tasmanian Devils were dying off like crazy due to the same tumor that was spreading through bite wounds around the mouth. I’ve recently read of a cancer in dogs that is considered to be the oldest continuous cancer, spread over thousands of years.

With this in mind, I don’t want any tumor cells to enter anywhere inside me, these cells have a habit of living in places they’re not supposed to be.

I would recommend the Radiolab podcast episode that talks about the Tasmanian Devils to anyone who finds the topic interesting.

What kind of casual (?) means of transmitting body parts did you have in mind?

Corrected link.

Well, just as a thought experiment, imagine a Mad Scientist trying it for kicks. (Or a Sane Scientist doing it to mice.) IANAOncologist, but my understanding is that part of the reason why cancers can be so intractable is that, even though cancer cells have gone berserk, they are still fundamentally speaking your own cells, making it difficult for your immune system to recognize them as The Enemy*. A transplanted (accidentally or on purpose) malignancy shouldn’t pose that problem–except that if you transplant a foreign organ into someone, you have to give them “anti-rejection” (that is, immunosuppressive) drugs.

*And also making it harder to come up with chemicals that are harmful to cancers that aren’t also harmful to some of your own healthy cells, as opposed to some very distantly related critter like a bacterium, where we can find or invent antibiotics that are deadly to them but harmless to us eukaryotes.

HeLa cells were injected into people (prisoners, IIRC) and *mostly *didn’t take. I think there was one guy who sustained the (infestation of?) HeLa cells for a few weeks, before throwing them off. He was (probably) immunologically intact. One wonders what might have happened if he was immunosuppressed.

The sample size was small and the experiment is far too unethical to repeat, even on a small scale. However, given the natural development of transmissible tumors in dogs and Tasmanian devils, one wonders if HeLa (or some other tumor) could become easily transmissible if injected (maybe serially) into a larger population.

My info on HeLa cells comes from “The Immortal Life of Henrietta Lacks,” author Rebecca Skloot, highly recommended reading.

My understanding is that the tumors in Tasmanian Devils are transmissible because of genetic similarity within the species due to inbreeding. The problem exists for domestic dogs for similar reasons.

I think with the Devils it’s something to do with the outer cell that makes the cancer undetectable to the immune system, not sure how small the gene pool is. With dogs, we are talking 11,000 years over a variety of dogs, I think inbreeding is only a factor in purebreds, the majority of dogs are not.

We are genetically similar enough to be infected by enough stuff, I still don’t want any cancer stuff anywhere near my insides.