Contradicting Previous Study, Cancer Risk Has Strong Environmental Component (washingtonpost.com)

The Real Dr John writes: A new study published in the journal Nature provides evidence that intrinsic risk factors contribute only modestly (less than ~10–30% of lifetime risk) to cancer development in humans (abstract). An earlier study had found that the more stem-cell divisions that occurred in a given tissue over a lifetime, the more likely it was to become cancerous. They said that though some cancers clearly had strong outside links – such as liver cancers caused by hepatitis C or lung cancer resulting from smoking – there were others for which the variation was explained mainly by defects in stem-cell division. The new research shows that the correlation between stem-cell division and cancer risk does not distinguish between the effects of internal (genetic) and external (environmental) factors such as chemical toxicity and radiation. They also found that the rates of endogenous mutation accumulation by internal processes are not sufficient to account for the observed cancer risks. The authors conclude that cancer risk is heavily influenced by environmental factors.

Comments

Interesting.

[Anonymous Coward]

My mom died of breast cancer. She never really smoke or drank, and ate fairly healthy, at least by the standards of the day. However for a lot of years we lived next door to farmfields that they sprayed with pesticides from airplanes, and it got to the point where we stopped drinking water from our well.

Makes me wonder if that could be a connection.

Re:Interesting.

[dwywit]

I've told my daughter that hairdressing is not a career option. Have you smelled some of the "product" they use? It becomes clearer with a little research - coaltar or benzine-derivative hair dyes. Doing your own hair once in a while - fine. Exposing yourself daily to that stuff *has* to have an effect.

Re:Interesting.

[Locke2005]

Wanna know the best protection against breast cancer? Popping out a new kid every year. Yeah, environmental factors play a role in cancer, but some of the "controllable" environmental factors may be worse than the cancer risk.

Re:Interesting.

[RobertM1968]

Wanna know the best protection against breast cancer? Popping out a new kid every year.

Did that line work?

Re:Interesting.

[tempmpi]

Well, the pill is an environmental factor, but it works both ways. It seems to increase breast and cervical cancer rates, but decreases the risk for Ovarian, womb and bowel cancers.

Re:Interesting.

[jblues]

I read a study once that most men die with (but not of) prostate cancer.

Re:Interesting.

[JoeMerchant]

The point where you probably should have stopped drinking from your well was probably a few months after the first pesticide use started.

In Florida, there's a huge difference between shallow wells and the deep aquifers. In the 1950s, when my father was growing up, all you had to do was dig a hole 12" deep and most days there would be clean drinking water there. When I was growing up in the 1970s, the shallow water table had dropped from just below the surface to 10 to 20' down, but you wouldn't drink shallow water anymore because it was all so polluted by then. If you were going to drink well water, you wanted to taste the sulfur in it to be sure it was coming from the deep (160'+) aquifer.

Now, there's talk of "recharging" the deep aquifers with river water - what could possibly go wrong with that scheme?

Re:Interesting.

[HiThere]

In Bangladesh there was also a difference between shallow wells and deep wells. The water from the deep wells was loaded with arsenic. So deep doesn't automatically mean good, even if it hasn't been recharged.

And bottled water is frequently contaminated with plasticizers. And distilled water is lacking in trace minerals (bad ionic balance). And water run through ionic filters generally contains too much salt (as well as plasticizers). Etc.

I generally drink tap water, and hope the water company is doing a decent job.

Re:Interesting.

[Anonymous Coward]

Don't be a twit.

The parent poster proves exactly what was intended: That certain factors apparently do not affect certain people in any measurable way.

That's all. There was no attempt at skewing statistics or anything like that. Just an example or two.

Relax.

Re: Interesting.

[sonamchauhan]

Or else, proved nothing. There is not a way of knowing whether his relatives would have lived years or decades longer without these occupational exposures.

Re:Interesting.

[YoungManKlaus]

Thats why you wear one-use gloves when dying ...

Re: Interesting.

[Applehu Akbar]

Anecdote n: A data point that supports the other guy's hypothesis.

Re: Interesting.

[HiThere]

Yes, but so far the state hasn't taken over the local water company where I live.

Re:Interesting.

[dsmatthews9379]

Correct, your mother's risk of breast cancer could have been increased by her local environment, https://en.wikipedia.org/wiki/...

Re:Interesting.

[dsmatthews9379]

Men can get breast cancer too, but they can't pop out kids.

Re:Interesting.

[Swave An deBwoner]

I'm not saying that deep wells are necessarily free of arsenic, but your characterization of the cause of arsenic poisoning in Bangladesh is at odds with what was reported here:

http://science.time.com/2010/06/19/study-says-arsenic-poisons-millions-in-bangladesh%E2%80%94but-theyre-not-the-only-ones/

Millions of tube wells were drilled to provide villagers with clean water, but many of them were dug into shallow layers of ground that had naturally occurring arsenic, contaminating the water.

Re: Interesting.

[sonamchauhan]

Correct. Improbable for sure :) ... but not impossible.

I'll go with the probable option - its more ... certain. :)

No shit

[penguinoid]

Everyone who knew anything about the subject knew that cancer has a strong environmental component. What the previous study had done was merely verify something lots of people already expected, namely that cell division (and especially stem cell division) gave you a risk of cancer due to inherent mutation rates.

Re:No shit

[penguinoid]

That's the problem with science. You can have all the hypotheses you want, but then you have to prove them. Everyone may know better, but unfortunately, science requires actual data.

I believe you meant, fortunately science requires actual data.

Re:No shit

[manu0601]

fortunately science requires actual data.

Except cosmology and string theory, which are exempted from experimental testing but are still called science

Re:No shit

[penguinoid]

Nothing says the testing has to be by performing experiments. That just happens to be the simplest way to test a theory.

Environmental mean...?

[PuckSR]

Can't wait to see all the anecdotes about chemicals that cause cancer.

This study is not stating that if we all lived in a paleo-era utopia that we wouldn't get any cancer.
It is simply stating that cancer isn't pre-cooked into our lives. If we lived in a perfectly sterile environment and did not expose ourselves to any energy of any kind, we would be very unlikely to develop cancer. We would just die due to a vitamin D deficiency and a lack of human contact.

Three part cancer risk

[Yergle143]

I work in the Cancer field here's my take home take.
The Individual probability for Cancer risk is in three parts.
1/3 Genetics: Beyond your control, a complex interplay of genes can lead to cancer.
1/3: Environment: Within your control there is a known influence of diet, chemicals, radiation, pollution etc. Lifestyle in other words can impact this component.
1/3 Random Chance: Billions of cell divisions occur to in our lives. The protein machinery that makes this happen has incredible fidelity but mistakes inevitably occur and this DNA damage can cause cancer, usually later in life. There is no lifestyle choice that an individual can make to prevent this damage from occurring. I would also lump into random chance the random inflammatory insults that occur over a lifetime -- a cold at a young age that damaged a subset of lung tissue that mutated the p53 gene giving rise to etc.
The linked paper/story reveals a raging controversy between constituencies for each part of the cancer risk pie. The losers are the patients/public who are misled by either an indifference to risk aversion or a single minded overestimate of the benefits of lifestyle. Its all three.
 

Re:Three part cancer risk

[turkeydance]

that means 2/3 of the risk of cancer is unaffected by efforts to avoid it.

Re:Three part cancer risk

[tlhIngan]

1/3 Random Chance: Billions of cell divisions occur to in our lives. The protein machinery that makes this happen has incredible fidelity but mistakes inevitably occur and this DNA damage can cause cancer, usually later in life. There is no lifestyle choice that an individual can make to prevent this damage from occurring. I would also lump into random chance the random inflammatory insults that occur over a lifetime -- a cold at a young age that damaged a subset of lung tissue that mutated the p53 gene giving rise to etc.

This is also beneficial because it's how evolution happens - random genetic mutations potentially give us traits that make us more (or less) successful at surviving.

The problem is the cell has lots of mechanisms to detect copy errors - there are proofreaders to ensure the right bases are joined together, there are cell division mechanisms that detect abnormalities and cause the cell to commit suicide, etc. And they're remarkably effective, but not 100%. That's good in that random genetic mutations are necessary for life, but bad in that sometimes the mechanisms fail to detect a cancer condition and cause cell suicide. (It's a problem of large numbers - even if it was 99.99999% effective, enough cells divide all the time that the failure of detecting the mutation means you will get lots of them in the end.

Random errors happen. But they aren't all bad, and they happen remarkably often due to the law of large numbers. Not every mutation will turn into cancer, after all.

Re:Three part cancer risk

[Yergle143]

Yep. But cancer is complex, not all die from it, and you have to assess it tissue by tissue. The male probability of prostate cancer goes with your age but most succumb of something else.

Re:Three part cancer risk

[Yergle143]

Remember it's only mutations to the germline (eggs and sperm) that propagate so the developmental buildup of damage is comparatively silent in an evolutionary sense unless it stops you from passing on your genes. Cancer sucks, in the modern world the old folks can still contribute but the alarm clock for the reaper was set during the stone age.

Re:Three part cancer risk

[Anonymous Coward]

That's a very very simplistic way of looking at it.

If your entire life you are smoking and working in an asbestos project without proper breathing apparatus, then that 1/3 environmental becomes 99% environmental.

Same with breast cancer - 90%+ chance of breast cancer by age 60 if you have some specific genes. So where is rest of the pie?

Talking about 1/3 this, 1/3 that is stupid and simplistic. Don't do it, especially when it comes to individual cases.

Re:Three part cancer risk

[penguinoid]

that means 2/3 of the risk of cancer is unaffected by efforts to avoid it.

Keep in mind that this is probably an estimate and definitely after accounting for the many many things we do to avoid cancer, particularly government banning or requiring warning labels or use restrictions on carcinogenic chemicals. If we decided it was OK to use highly carcinogenic chemicals as food flavorings then suddenly the ~33% environmental contribution would probably rise to ~90%.

Re:Three part cancer risk

[khallow]

that means 2/3 of the risk of cancer is unaffected by efforts to avoid it.

Depends on the efforts. penguinoid already mentioned how you can make it worse. If on the other hand, you have nanoscale machinery in your body actively hunting down and destroying pre-cancerous growths, it's going to be a lot lower.

everything gives you cancer

[turkeydance]

Joe Jackson https://www.youtube.com/watch?...

Re:The healthy continue to blame the sick...

[Coren22]

in the developing world 70% will die from it or its complications and in the developing world 45%...

Did you perhaps mean developed on that second one? Otherwise I have to ask, which is it?

Funding Wanted

[Anonymous Coward]

If anyone has $100M US, I'd be glad to research any conclusions they'd like...

Known for some time

[nospam007]

"was explained mainly by defects in stem-cell division"

And lots of those defects are happening in your fat for some reason, causing also all sorts of inflammation, besides the cancer angle.

So you'd better get to that single digit fat percentage if you want to live a long healthy life.

Radionuclide effluents from Nuclear power and Coal

[MrKaos]

We have to exclude enriched radionuclides from Nuclear Power plants as an environmental factor causing cancer or any form of genetic disease because Nuclear power is not part of the environment and anything that gets out is not part of 'normal' operations. Even if it did it wouldn't be that bad anyway, our generation should not be concerned, it's NIMG.

The (un)enriched radionuclides from coal are really bad though. Even knowing they are there will cause generations of cancer so it's better to not know.