Comment by Pica_soO | Hacker News Reader

Comment by Pica_soO | Hacker News Reader

Parent Full thread

There is a corellation between beeing hunted by a predator (external death stimulus) and not beeing hunted by a predator (internal death stimulus). Predators life a dangerous life, for them theire daily activity is a eds. Obviously the benefits of cancer suppressing DNA in a population apply only if you are either to well hidden (naked mole rat, sloth) or to big to be predated (Rhino, Elephant, Whale). Sorry, we as humans are part of a predatable species, so live fast and leave a devourable corpse for your descendants to mourn was our main strategy. If in search for human compatible cancer avoidance, the biggest interest should be on the most well hidden monkey - or the biggest (silverback).

Interesting is also how the re-productive cycle factors into this. If a individual takes a long time to grow up- cancer is a selector tortoises, if the reproduction is fast (mice/birds) cancer is basically not important. If every mice would get cancer after year 2 - the species still would continue.

The following statement from the article is at odds with your speculation:

"Peto noted that, in general, there is little relationship between cancer rates and the body size or age of animals."

According to your speculation, you would expect that large and old animals would have a lower cancer rate.

Large and old are factors on the indivdual. But preyed upon is a factor impacting on the history of a species (all individuals).

So a (in evolutionary terms recently) huge, old rodent, still carrys the baggage of the past.

The size matters only in evolutionary time lengths - if a lot of individuals are to big to be predated.

PS: Was the factor of age reduced cell division as a tumor hiding factor even removed from the statistics?

Finally what about metabolism rate as amplifier of cancer? Slow metabolisms with a constant intake (no peaks of production and consumption), no constant heating costs due to small body size.

My "Speculation" is just there to remind people that taking some individual factors and correlating them into seemingly meaningful results ignores the complexity of the situation.

Please note that the word "animal" in the quote of Peto's paradox and my comment refers to "species" and not an "individual", as you infer in your reply.

So yes, the species will include the baggage of the past.

Which in itself is interesting.. which animals did we know to continuously grow for live and only recently hitting upon hard times.

Dinosaurs- but birds do get cancer and are not predated- crocodiles and Commode-dragons seem to be excluded. Maybe im wrong here.

As weight and lifespan increase, unchanging cancer rates per capita actually mean substantially increasing cancer resistance per cell/year, as discussed here: https://news.ycombinator.com/item?id=14699628

Of significant note is the naked mole rat (a 30g 8cm rodent so about the size and weight of the average house mouse) which for a long time was though immune to cancer (they're not, but they are ridiculously resistant to it).

> live fast and leave a devourable corpse

Ah, you know my family motto!

I am curious why "human compatible" patterns would be only found in primates etc.? Aren't these about molecular mechanisms and proteins? Is it hard to translate the results to humans if some promising mechanism is found in more basic molecular level?

Reply on news.ycombinator.com