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My understanding is that cancer kills you late enough in your life to has little impact on your ability to reproduce, and thus fitness in the evolutionary sense

My understanding is that cancer kills you late enough in your life to has little impact on your ability to reproduce, and thus fitness in the evolutionary sense. https://www.cancerresearchuk.org/health-professional/cancer-statistics/mortality/age#heading-Zero https://www.cancerresearchuk.org/health-professional/cancer-... These are deaths / 100'000 people. It's a bit difficult to judge precisely in that resolution, but death by cancer is <1%/year before the age of 40. That was roughly the life expectancy (assuming you made it past childhood, big if), for humans during most of their evolution. So the likely answer is that it never mattered to our body (or survival) to combat cancer effectively.

DoreenMichele 7y ago
Or, alternately, we produce plenty of them normally in our youth so as to keep cancer from getting a good hold and we develop deficiencies that reduce their production as we age and this allows cancer to go from whatever stuff causes it floating around the body randomly to full-blown tumors and the like. Either way, your framing has zero bearing on my point. If they can produce them in quantity in vats for purposes of combatting cancer, why not produce them in quantity in the body? That's my point.
- Nitramp 7y ago
  > Either way, your framing has zero bearing on my point. If they can produce them in quantity in vats for purposes of combatting cancer, why not produce them in quantity in the body? That's my point. I tried to answer "why are these not naturally produced in quantity by your body". Are you asking why the scientists didn't alter human bodies to artificially produce these cells in quantity inside the body? No idea, but that does sound a lot more difficult/dangerous than producing them in a vat?
  - DoreenMichele 7y ago
    That wasn't what I asked: "Why isn't your body already making enough of these.. And I don't think it is dangerous to wonder what the hold up is and try to do research to answer that question. But it seems like no one here is actually getting what I'm trying to say. It's late. I'm tired. Whatevs.
firethief 7y ago
Human evolutionary fitness goes beyond individual reproductive fitness, for kin-selection sort of reasons. That's why e.g. women are generally capable of living well beyond menopause
- Nitramp 7y ago
  Yes, but if you're dead by 50 anyway for unrelated reasons, there's still not selective pressure to combat cancers that only kill you at 60+. That's regardless of your individual reproduction or your contribution to the group's fitness.
jcranmer 7y ago
> death by cancer is <1%/year before the age of 40. That was roughly the life expectancy (assuming you made it past childhood, big if), for humans during most of their evolution. My understanding is that Paleolithic peoples generally had a life expectancy of about 50-60, assuming that you survived childhood. The development of Neolithic probably lowered life expectancy somewhat (since, basically, people eating an agricultural diet are essentially chronically malnourished until sometime in the Early Modern). Nowhere have I seen any indication that the life expectancy of humans, at any point in time, was as low as 40.
- cmrdporcupine 7y ago
  There's a lot of bad stats out there that are based on averages, which are distorted by the high infant and childhood mortality rate of pre-industrial humans.
- Nitramp 7y ago
  I'm not by any means an expert, but the very first Google hit (wikipedia as usual) gives: > Based on Neolithic and Bronze Age data, the total life expectancy at 15 would not exceed 34 years. https://en.wikipedia.org/wiki/Life_expectancy https://en.wikipedia.org/wiki/Life_expectancy Which in turn cites this article: https://onlinelibrary.wiley.com/doi/abs/10.1002/ajpa.1330300314 https://onlinelibrary.wiley.com/doi/abs/10.1002/ajpa.1330300...

DoreenMichele 7y ago

Or, alternately, we produce plenty of them normally in our youth so as to keep cancer from getting a good hold and we develop deficiencies that reduce their production as we age and this allows cancer to go from whatever stuff causes it floating around the body randomly to full-blown tumors and the like. Either way, your framing has zero bearing on my point. If they can produce them in quantity in vats for purposes of combatting cancer, why not produce them in quantity in the body? That's my point.

Nitramp 7y ago
> Either way, your framing has zero bearing on my point. If they can produce them in quantity in vats for purposes of combatting cancer, why not produce them in quantity in the body? That's my point. I tried to answer "why are these not naturally produced in quantity by your body". Are you asking why the scientists didn't alter human bodies to artificially produce these cells in quantity inside the body? No idea, but that does sound a lot more difficult/dangerous than producing them in a vat?
- DoreenMichele 7y ago
  That wasn't what I asked: "Why isn't your body already making enough of these.. And I don't think it is dangerous to wonder what the hold up is and try to do research to answer that question. But it seems like no one here is actually getting what I'm trying to say. It's late. I'm tired. Whatevs.

firethief 7y ago

Human evolutionary fitness goes beyond individual reproductive fitness, for kin-selection sort of reasons. That's why e.g. women are generally capable of living well beyond menopause

Nitramp 7y ago
Yes, but if you're dead by 50 anyway for unrelated reasons, there's still not selective pressure to combat cancers that only kill you at 60+. That's regardless of your individual reproduction or your contribution to the group's fitness.

jcranmer 7y ago

> death by cancer is <1%/year before the age of 40. That was roughly the life expectancy (assuming you made it past childhood, big if), for humans during most of their evolution. My understanding is that Paleolithic peoples generally had a life expectancy of about 50-60, assuming that you survived childhood. The development of Neolithic probably lowered life expectancy somewhat (since, basically, people eating an agricultural diet are essentially chronically malnourished until sometime in the Early Modern). Nowhere have I seen any indication that the life expectancy of humans, at any point in time, was as low as 40.

cmrdporcupine 7y ago
There's a lot of bad stats out there that are based on averages, which are distorted by the high infant and childhood mortality rate of pre-industrial humans.
Nitramp 7y ago
I'm not by any means an expert, but the very first Google hit (wikipedia as usual) gives: > Based on Neolithic and Bronze Age data, the total life expectancy at 15 would not exceed 34 years. https://en.wikipedia.org/wiki/Life_expectancy https://en.wikipedia.org/wiki/Life_expectancy Which in turn cites this article: https://onlinelibrary.wiley.com/doi/abs/10.1002/ajpa.1330300314 https://onlinelibrary.wiley.com/doi/abs/10.1002/ajpa.1330300...