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Comment by zamalek | Hacker News Reader

> the patient population is too small.

I think that cancer is one of the great filters. At some point a species will develop an unreliable way to treat cancer (chemotherapy); at which point cancer becomes a genetic problem as natural selection is displaced by medicine. Over many generations, this will kill a species unless a reliable cure is found - we seem to have that cure. Our cure is symptomatic (cancer being the symptom) but the same technology could eventually be used for designer genetics.

Essentially, more and more people are going to rely on this treatment until we are able to completely eradicate hereditary cancer. Probably not in our lifetimes.

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What displacement of natural selection? Hereditary cancers are the exact type of cancers that haven't been affected by natural selection since they generally are post-reproduction age.

Furthermore, eradicating hereditary cancer (and many other diseases) is technologically possible already (screening of embryos, genetic testing of parents) but it's socially and politically complex; we as a society currently don't want to e.g. enforce restrictions on procreation just to prevent these diseases.

This discussion already happened below.

What is the selective pressure /for/ cancer-predisposing genes? And it's not as if most cancers act as a reproductive filter -- the majority of them emerge well after the onset of reproductive ability, drastically reducing, if not eliminating, their selective effect.

> What is the selective pressure /for/ cancer-predisposing genes?

Evolution does not and never has selected /for/ things. It is a process of elimination. What this means is that, since the advent of chemotherapy, we have eliminated selection /against/ certain types of cancer.

> the majority of them emerge well after the onset of reproductive ability

Correct, we have never had an impact on that and likely won't for a very long time (we don't know enough about our genome to do so). As-per this study, we have been curing cancer in children (as we absolutely should) with very little knowledge as to how/why they developed cancer so young. Will their children also be at risk for leukemia? What about their millions of descendants? We don't know. If treatments like this work out then we might not have to care.

Actually evolution may well be selection against cancer in older people. (may is key - we don't know for sure) Enough Young girls of breeding age have a small tendency to breed with old men. This increases our lifespan by ensuring those who have whatever genetics it takes to live older have more children. It is a small effect, but it is something.

But cancer isn't primarily a genetic problem; it's a consequence of the way our bodies work at the cellular level. We all accumulate genetic damage over time from a variety of sources, and we'll all get cancer eventually if something else doesn't kill us first.

That is the story for most people today but is not the entire story. If your mother had breast cancer then you are at a higher risk - if not for genetics that would be magic. That is why I specifically said "hereditary cancer."

Yep, other hereditary cancer syndromes too, such as Von-Hippel Lindau, which is a mutation in a tumour suppressor gene.

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