3 ms·
Clonally transmissible cancers are typically only seen in highly inbred populations. Tasmanian devils qualify because they went through a population bottleneck
by dcolkitt 7y ago
Clonally transmissible cancers are typically only seen in highly inbred populations. Tasmanian devils qualify because they went through a population bottleneck when they first colonized the island. Dogs qualify because of human breeding. (It's pretty unlikely that CTVT could be transferred to a wolf, even though pet dogs and wolves are the same species.)
The reason most cancers aren't transferrable, is the same reason that organ transplants are so hard. Most individuals in most species have unique antigen profiles. The immune system attacks any foreign bodies without matching antigens. An internally generated tumor works because it's cloned from an individual's own cells.
But a foreign tumor, is very unlikely to have a matching antigen profile. Therefore the immune system will attack and destroy with extreme prejudice. However a highly inbred population may lack the sufficient genetic diversity to have individually unique antigen profiles. In the extreme case if we were all clones we could pass tumors back and forth with ease.
The short answer is that it would be virtually impossible to see any widespread cases of clonally transmissible cancers in non-immunocompromised humans.
- Loughla 7y agoSo if you have a population of humans who, for generations, have selected genes via inbreeding, would it be a thing to have transmissible cancer? I'm thinking of the Amish population near my hometown that has definite inbreeding traits and particular disabilities associated with inbreeding in their bloodline/families. Would it be possible for them to develop some kind of transmissible cancer?
- weinzierl 7y agoSo does that mean that cancer is contagious among identical twins?
- moftz 7y agoI suppose it depends on their individual immune systems. If they didn't live in close contact, they may not share the same immune system. One may have a weaker immune system than the other making it possible for the cancer to spread easily one way but not the other.
- dcolkitt 7y agoInteresting question. I suppose so. I know identical twins can typically receive organ transplants from each other with complications. So theoretically they should be able to receive tumor transplants (which is what clonal transmissible cancer is).
- iskander 7y agoI wouldn't be so sure, a cancer that doesn't express classical MHC but still manages to suppress NK cells has a chance. It would probably have to master a few other immunosuppressive pathways but it's not beyond imagination. Transplanted HeLa cells were shown to engraft in unrelated human "subjects" (in some truly evil experiments by https://en.wikipedia.org/wiki/Chester_M._Southam https://en.wikipedia.org/wiki/Chester_M._Southam), other cell lines probably have the same capacity.