
How a 6k-Year-Old Dog Cancer Spread Around the World - hirundo
https://www.wired.com/story/how-a-6000-year-old-dog-cancer-spread-around-the-world
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knolax
Does anyone have more specifics on how the cancer avoids an immune system
response?

~~~
kryptiskt
The article in the Atlantic
([https://www.theatlantic.com/science/archive/2019/08/ctvt-
tum...](https://www.theatlantic.com/science/archive/2019/08/ctvt-tumor-broke-
all-rules/595246/)) said:

"Also, the majority of those mutations, including almost all of the recent
ones, are neutral. They don’t seem to benefit the tumor in any way. Again,
that’s very different from most cancers, which are constantly adapting to
outfox their hosts’ immune systems, or to grow a little faster, or to spread
to new areas. Not so with CTVT. “We think that the cancer is not adapting
anymore,” says Adrian Baez-Ortega, who was one of the main researchers on the
study. “Maybe it doesn’t really need to.”

Perhaps, early on in CTVT’s history, it found such thorough ways of escaping
the immune system and jumping into new hosts that no further tweaks were
necessary. Or perhaps it no longer imposes enough harm on its hosts to warrant
a counterattack. It’s rarely fatal, after all, and if dogs are otherwise
healthy, it doesn’t grow very fast. “The tumor and the dogs aren’t competing
against each other anymore,” Baez-Ortega says. “They’re coexisting. The cells
behave like cancer cells, but the ecology of the tumor is that of a parasite.”
And a fairly benign one at that."

~~~
setr
>The tumor and the dogs aren’t competing against each other anymore,” Baez-
Ortega says. “They’re coexisting. The cells behave like cancer cells, but the
ecology of the tumor is that of a parasite.” And a fairly benign one at that."

This is pretty much the story of any “old” virus; new viruses (new mutations,
species jumping, etc) tend to kill, but they optimize towards coexistence,
since killing the host reduces reproduction/spread opportunity.

So eventually they become benign within a population (both by their evolution,
and adaptation of human immune system) and only become threatening again when
encountering a new population (eg an “infected” city-man visiting rural
populations).

Notably, due to the more rapid spread of disease in cities, due to higher
density, city-folk tend to have more benign/evolved diseases than rural
populations.

Which I _think_ is also the answer to my childhood question: why did the
europeans famously have diseases to spread and kill native americans with..
but the native americans could offer no such devastating disease in return?
Both groups should have been encountering new diseases; my answer being that
the native americans were carrying fewer suppressed diseases.

There’s of course the popular answer that europeans were more evil/willing to
spread disease with things like chicken-pox blankets.. (and catapulting
rotting animals), but it’s really difficult to imagine native americans would
be so primitive that couldn’t learn/mimick the idea... or perhaps its just
written out of the history books..

But I never found confirmation on this

~~~
reallydude
CCP Makes a pretty good case regarding livestock -
[https://www.youtube.com/watch?v=JEYh5WACqEk](https://www.youtube.com/watch?v=JEYh5WACqEk)

America did offer a new disease that ravaged Europe. Syphillis.

~~~
weberc2
And like this disease, Syphillis was initially terrifying, with flesh falling
off of victims' faces, before the disease "decided" that it was better to let
its victims live with genital sores rather than die horrific deaths. For the
disease, it could infect more people on a longer-living host.

