alt.hn

7/30/2026 at 2:15:19 PM

Why DNA damage from smoking and UV rays cause cancer in some but not others

 https://www.cam.ac.uk/research/news/study-reveals-why-dna-damage-from-smoking-and-uv-rays-may-cause-cancer-in-some-people-but-not-others

by gmays

7/30/2026 at 8:43:40 PM

F* cancer. On my mother's side, her mom and sister died of breast cancer, her other sister caught it early, her brother died of cancer (throat or lung, not sure). She removed her breast 20 years ago at almost 50, went through chemo and radiotherapy, she was a survivor, cured. Just a month ago got headaches and turns out new brain tumor. Neurosurgeons removed it, but against all odds nothing to do with the old cancer, not a metastasis, but a new primary wildtype glial grade 4 tumor. It's just not fair.

by dsego

7/30/2026 at 3:06:45 PM

Anecdotally, whenever I go swimming with my kids in the summer, and I don't put sunscreen on right away, but let myself get some intense direct sun, I feel good and sleep really well that night.

As long as I don't let myself get in a red, sunburn situation.

by aantix

7/30/2026 at 3:22:52 PM

The number one reason I wear an Apple Watch all summer is the UV index complication. If the number is at 4 and trending down I let the kids run free.

by krrrh

7/30/2026 at 3:25:07 PM

Interestingly the best time to go out is at solar noon, when the UVB/UVA ratio is higher. Just go for a shorter amount of time to compensate for the higher overall intensity.

by pazimzadeh

7/30/2026 at 3:37:06 PM

That's only if you don't have a lot of time out. If you're planning to be out for a while I'd avoid being too exposed during the 12-3 window.

by tartoran

7/30/2026 at 4:08:35 PM

I agree, but you can titrate your exposure. So at the beginning of the season, in the 12-3 window you can start by going 5 mins without sunscreen for a few days, then 10 mins, then 20 etc. depending on your skin type.

The worst thing to do is to go from low exposure (i.e. winter months, or just constant indoor time) to long periods of exposure, even with sunscreen.

by pazimzadeh

7/30/2026 at 3:35:59 PM

Care to explain? Isn't UVB more harmful than UVA?

by Rnonymous

7/30/2026 at 4:06:02 PM

No, UVA is stronger and more harmful. UVA penetrates deeper in the skin, since it's stronger. UVB stimulates Vitamin D production, while UVA doesn't.

So almost anything that is "UV-blocking" (sunscreen, UV-treated glass) gets rid of all of the beneficial UVB before UVA starts getting reduced. So you are actually enriching your exposure to the most harmful UV type, and not making Vitamin D.

This might explain the paradoxical finding that people who use sunscreen more can have higher rates of skin cancer

https://pmc.ncbi.nlm.nih.gov/articles/PMC10840669

by pazimzadeh

7/30/2026 at 6:31:52 PM

Confounding by indication.

People who spend more time outdoors are more likely to try to wear sunscreen, as are people who already got a lot of pre-existing risk to excessive sun exposure.

Key word on try as its greatly assuming there isnt a wide audience who do use sunscreen, then just apply it in poor amount, or never re-apply but enjoy staying out far longer than most do in the sun feeling they're oh so very protected.

Spray sunscreens for example are just about useless, as are those solid stick applicators. They only get a fraction the amount you need for the rated protection. The biggest issue with sunscreen relates to companies selling sub par "convenience" slop, often right beside their other products some of which might actually be half decent.

by miladyincontrol

7/30/2026 at 8:55:00 PM

Sure that’s a theory, but hasn’t been proven. If I recall, the study showed that heavy sunscreen use amongst sunscreen users was associated with higher cancer rates.

Secondly, if sun exposure is really that bad then how do you explain why most skin cancers are on the trunk and thighs rather than more exposed areas like hands and arms?

The simplest answer is it’s not sun exposure that’s bad but sudden high exposure after non-exposure (repair mechanisms can’t keep up with damage).

Not sure why I’m being downvoted. I guess there’s a lot of sheep among us. If anything I said is incorrect, please show me the evidence.

by pazimzadeh

7/30/2026 at 3:15:53 PM

I can spend a solid hour in the sun before I start to burn, assuming I have a hat on my head.

I've also noticed some correlation between my diet and how fast I burn. Whenever my metabolism is running at/near ketogenesis, it seems like it takes a lot longer for the sun to affect me.

by bob1029

7/30/2026 at 3:22:23 PM

Yes, some stuff make your skin more sensitive to light than others. For example, you should avoid vitamin A creams and some herbs during summer because they increase risk of permanent skin discoloration.

by Ralfp

7/30/2026 at 9:09:44 PM

also: citrus- wash your hands after.

by butvacuum

7/30/2026 at 3:25:27 PM

Which herbs

by pazimzadeh

7/30/2026 at 3:43:51 PM

I experienced similar reaction when i was doing keto. It became far more difficult to burn that summer

by spacephysics

7/30/2026 at 3:56:59 PM

Why did you stop?

by ShinyLeftPad

7/30/2026 at 3:37:37 PM

Just so you know, burning & cancer isn't the only reason to avoid strong sunlight - it also causes skin aging (i.e. wrinkles). If you don't want to be super wrinkly when you're old, wear suncream!

by IshKebab

7/30/2026 at 3:54:58 PM

When we were dating, the first thing my now wife did was get me on a regimin of sunscreen and tretinoin. I now have significantly fewer wrinkles than my younger siblings (2-3 years).

by causalmodels

7/30/2026 at 6:32:34 PM

Most likely that’s the nitric oxide (not to be confused with nitrous oxide) that is a biproduct of vitamin d synthesis which requires UV light. It is a natural muscle relaxer and is generally considered good for blood pressure and heart health in general.

by milesvp

7/30/2026 at 3:09:35 PM

Vitamin D deficiency

by ThrowawayTestr

7/30/2026 at 3:13:53 PM

Definitely not. Vitamin D takes a while to synthesize and build up. A quick fix like this isn't possible.

by GlickWick

7/30/2026 at 3:53:23 PM

It's just that getting sun is healthy (in moderation) and our body reward us, we have this new anti-sun obsession which is likely to cause many health (and mental health) issues

by pixel_popping

7/30/2026 at 4:11:03 PM

I don't think it's that simple, and making it seem that way is counter-productive towards understanding what we should/shouldn't be doing.

There's no anti-sun obsession, either. Sunscreen isn't anti-sun, and people are well aware that Vitamin D synthesis is an issue in farther northern/southern latitudes. There's definitely an increased recognition scientifically that excessive sun is extremely bad, though.

by GlickWick

7/30/2026 at 4:36:17 PM

I would assume that many are taking Vitamin D, but there is still a major difference, if I spend few days no-lifing and I suddenly go out in the hot sun and comeback home 30min later, I feel much better, something happens internally, could be from the light itself, unsure, but I'd say for example to fight off depression, getting under the sun is quite powerful and will definitely improve your chances of getting out of it.

I let my 2-year old child (she is also taking Vit D - 300iu a day) under the sun in the garden quite a lot on/off (I'd say probably 1h a day in total) and I find that she sleeps much better and is more calm in the evening as well, I can't say the same if we do an outing to the mall, something is clearly different/rewarding.

by pixel_popping

7/30/2026 at 3:34:47 PM

I typically do the same thing. I only wear sunscreen if I am planning on being in direct sun for an extended period of time where I can't easily get back in the shade.

The more you're able to build up a base tan the less you need it to avoid a burn at least.

by brightball

7/30/2026 at 3:47:12 PM

I'm pretty light skinned and the burn pretty easily. I just put on sunscreen by default when going hiking/mountain biking. I'm really excited for the new sunscreens coming out here in the US that have those new to us ingredients that the Euro's have had forever.

by vondur

7/30/2026 at 3:54:25 PM

Agreed completely. I also leverage sun shirts quite a bit.

by brightball

7/30/2026 at 3:40:06 PM

Isn't tanning basically body's reaction to cellular damage? It reduces further damage but that's due to damage done?

(It's largely irrelevant to myself, I pretty much burn immediately and don't / can't really tan, but my wife and her family tan well).

by NikolaNovak

7/30/2026 at 3:42:51 PM

30 years ago I was a lifeguard and got to experiment with this some. I can't tell you the biology specifically, but I have always tanned quickly. The less tan I am, the more easily I burn.

Always been that way for me at least.

by brightball

7/30/2026 at 3:52:54 PM

The damage gets healed at sleep. Tanning reduces the need to heal.

by worldsavior

7/30/2026 at 3:36:45 PM

So we're just out here perpetuating myths on here now as well?

by JoshGlazebrook

7/30/2026 at 3:37:13 PM

Correction - The less you need it to avoid a burn.

by brightball

7/30/2026 at 4:10:11 PM

I'm a pale-skinned redhead, covered in freckles. For me there is no such thing as a "base tan".

I get can get sunburnt from as little as 30 minutes in the sun at times, and I almost always wear sunscreen in the summer for that reason.

(Biggest issue is wearing sandals and forgetting to cover my feet, or when jumping in the lake after sauna and not covering up again quickly enough.)

by stevekemp

7/30/2026 at 3:48:25 PM

Very common press release/headline meme: the question in the title of the article is literally never answered (or the opposite of the headline's claim is true). This research plainly DOES NOT explain why certain mice got cancer and others didn't, let alone why smoking/UV rays cause cancer in some humans but not others. There was no control group for exposed mice that would've allowed them to look at which biological differences made one group get tumors and the others not (the study doesn't appear to actually be interested in that question).

The language here is also pretty hyperbolic. We've known for decades that certain gene mutations cause increased cancer risk in the context of a certain genetic background (BRCA1/2, etc.). Using language like "for the first time" is just juvenile, or purposeful lying at worst.

by TaupeRanger

7/30/2026 at 2:18:04 PM

In mice

by JoeAltmaier

7/30/2026 at 3:16:42 PM

Mice are used for inhalation and skin studies because they're cheap, we know their genome, they have a short lifespan for whole lifecycle observation and they're ideal for mapping to human respiratory and skin responses.

by htek

7/30/2026 at 3:22:31 PM

These comments are filled with people who believe that everyone else here is dumber than they are. Leaving shallow dismissive comments explaining something that doesn't need to be explained is like crack to them.

by add-sub-mul-div

7/30/2026 at 3:34:18 PM

It's a bit more than that.

The migration from mouse models to human understanding is long and complex, and although it's a meme, "in mice" is a good shortcut for saying "This is a good start, but it's not ready to extrapolate into conclusions against the impact to human beings".

https://www.in-mice.com/

by manarth

7/30/2026 at 3:08:12 PM

Mice smoke?

by baxtr

7/30/2026 at 3:10:06 PM

Only the cool ones

by theoreticalmal

7/30/2026 at 3:37:18 PM 

  > "Mice smoke?"
The experiment summary:

  > "The team bred four strains of mice.
  >  They then exposed the mice to a single dose of the liver carcinogen diethylnitrosamine (DEN).
  >  DEN is found in tobacco smoke."
They simulated the "consequences" of smoking in mice.

by manarth

7/30/2026 at 3:12:19 PM

When near the lab's Bunsen burner.

by pasc1878

7/30/2026 at 3:18:55 PM

Only if they grew up near a BBQ joint

by kraquepype

7/30/2026 at 3:13:07 PM

Even if smoking didnt cause cancer it would still be terrible.

6 months since i quit using nic gums.

by coolThingsFirst

7/30/2026 at 3:26:01 PM

I've only ever smoked like a quarter of one cigarette when I was eighteen and I thought it was fucking gross so I never picked up the habit (fortunately).

That said, I'm a pretty pale dude and my sister has gotten skin cancer twice now [1], so I've started getting a bit worried that that's going to happen to me. I've started wearing a baseball cap every time I go outside to protect my scalp (since my body has decided I don't need nearly as much hair anymore), I almost never go outside without jeans and often now a hoodie even when it's relatively warm outside. If I think I'm going to be outside for more than ~30 minutes, I wear sunscreen on the exposed parts.

I have to admit that I kind of hate it. I don't like the slimy feeling of sunscreen on my skin, I don't really like how hats feel on my head, and of course wearing a lot of clothes when it's warm outside isn't terribly comfortable.

[1] Fortunately caught very early since she gets frequent checks, so she's fine.

by tombert

7/30/2026 at 3:31:33 PM

Also share the icky for greasy sunscreen. But there are some with a matte dry texture that not only serves the purpose but also make your skin looks nicer, since it levels out those small color variations. It’s a big market, so they really do research on those things.

by pilgrim0

7/30/2026 at 3:36:36 PM

Sun shirts are a great option for me at least.

by brightball

7/30/2026 at 3:33:47 PM

A fairly bad sunburn was the reality check I needed to start scheduling annual screenings. 30 minutes or so a year for peace of mind.

by itsmartapuntocm

7/30/2026 at 3:37:39 PM

Check out mineral based sunscreens, I have sensitive skin and I find them infinitely more tolerable.

by thisoneisreal

7/30/2026 at 3:56:08 PM

Timing is also a big part. Going out for an hour at 1 pm can be a burn while going from 7 to sunset for the week might not even register.

If you must go out at certain times then the clothing selections from others are probably the best bet.

by zamadatix

7/30/2026 at 3:35:02 PM

A bit offtopic, but have you tried different sunscreen types? There are quite a lot of formulations from matte creams to solid sticks. Mentioned because I remember avoiding sunscreens precisely because of that slimy feeling I got from the drugstore ones, that is, until I found an "invisible" one that doesn't feel like anything at all on my skin.

by leawi

7/30/2026 at 3:37:18 PM

I have not. Do you have any recommendations for specific brands? I'll order a bottle and try it out.

by tombert

7/30/2026 at 4:48:23 PM

Different person here, but I've been using various Supergoop products for years and think they're all excellent. Their "Unseen Sunscreen" dries completely matte but is kind of pricey per ounce. I mostly use it on my face. "Play" is cheaper (especially if you get the 18oz pump bottle) and still a lot less greasy than most drug store sunscreens. I use it every day.

by joe5150

7/30/2026 at 3:49:04 PM

There are honestly quite a lot of them, I usually take whatever's on sale. My favorite so far is Haruhatu Airyfit, but I was also happy with La Roche-Posay (Athelios dry-touch) and Neutrogena (dry-touch or matte). I also like to take Abib stick with me when I travel, it's just really easy to reapply and fits in the pocket.

Edit: I'd also say avoid anything that says "moisturizing" unless you have a really dry skin, they all claim their product is not greasy, and they are all lying, from my experience.

by leawi

7/30/2026 at 3:34:10 PM

Strong recommend a UV umbrella. I also hate the feeling of sunscreen and will also fry the minute I so much as look at the sun.

Also, linen clothing. Far more comfortable in heat while keeping you covered. Hoodies and jeans sounds miserable.

by Mezzie

7/30/2026 at 3:44:04 PM

I've more or less gotten used to the jeans.

Probably due to a combination of undiagnosed autism and some very mild bullying in middle school (due to me growing rapidly and people making fun of me for wearing "short shorts"), I have been almost exclusively wearing jeans for everywhere but the gym since eighth grade.

The hoodies are a more recent thing and are more miserable. I'll check out linen clothing.

by tombert

7/30/2026 at 3:48:51 PM

Yeah, there are linen pants too, so you don't have to wear shorts if you don't feel comfortable showing your legs. Linen in general is a great option if you want to not die of heat and you don't feel like showing your whole body to the world.

Since you're autistic, you might want to buy them in person: the tactile sensation of linens can be pretty different, so you might want to touch them before buying if sensory issues are a clothing concern.

One thing to look out for is that a lot of clothing that will come up when you search for linen are linen blends, which are better than a hoodie by far, but aren't going to have the same breeziness as 100% linen. Also, 100% linen wrinkles, so you've got to hang it right out of the dryer if you care about that.

by Mezzie

7/30/2026 at 4:02:39 PM

I don't really have sensory issues and I don't get too picky about the textures of clothing. As I said, never actually diagnosed as autistic, I think I'm more borderline if I am.

Anyway, I'll take a look at some linen stuff. Probably worth an experiment if nothing else.

by tombert

7/30/2026 at 3:46:56 PM

I would bet on the sunscreen being a better protection since it also protects against reflected light, but UV umbrellas are so much more convenient. Takes 2s to take out rather than 5min to apply sunscreen properly.

(except when it's windy. Rain usually follows the wind, sunlight does not)

by Krssst

7/30/2026 at 3:52:13 PM

Good point re: wind. We don't really get substantial wind + sunlight where I live often. Definitely something to keep in mind.

I'm not sure re: the sunscreen being better. Maybe as a platonic ideal, but it's really easy to miss places when applying sunscreen, whereas a UV umbrella does cover everything with no fuss.

by Mezzie

7/30/2026 at 3:58:23 PM

How is UV umbrella different from any normal umbrella?

by ShinyLeftPad

7/30/2026 at 3:12:14 PM

Isn't this sort of like asking "Why does getting shot kill some but not other?" It depends on which part of the body was shot, and which part of the DNA was damaged.

by doctoboggan

7/30/2026 at 3:19:45 PM

The way I read the article was that cancer is caused by deficiencies in the body's repair mechanism. It appears as if some have a more robust mechanism than others, depending on genetics.

by mr_mitm

7/30/2026 at 3:26:00 PM

My mom had 14 siblings and only one of them got breast cancer (she was a nun and never breastfed which drastically increases a woman’s odds of breast cancer). But prior to that, her mother’s family, which was also large never had a case of cancer. My mom’s siblings also had around 30 kids between them some now in their 60s. There hasn’t been a single case of cancer amongst the kids either. So it’s something like 150 people with only one instance of cancer over the last 3 generations. There is definitely a strong genetic component to this.

by dyauspitr

7/30/2026 at 3:44:48 PM

Yes, genetics play a big part but my understanding that cancer is influenced by both genetic and environmental factors. It's possible to have similar habits in the family with respect to sun exposure, alcohol consumtion, diets etc..

by tartoran

7/30/2026 at 4:16:04 PM

Oh definitely, there’s a huge environmental component as well but good genetics really helps.

by dyauspitr

7/30/2026 at 3:15:38 PM

No. Genetics and nutrition make a big difference here. It is like one person is wearing a bullet proof vest and both were shot in the same place.

by Noaidi

7/30/2026 at 3:14:44 PM

This is why Zinc is needed to prevent cancer[1].

The gene they are focusing on in the study [2] is Methylated-DNA--protein-cysteine methyltransferase (MGMT) and it needs zinc as a cofactor [3].

Not enough zinc, lower MGMT, and less DNA protection and repair.

Nutritional deficiencies and genetic differences increase the risk of cancer.

[1] https://link.springer.com/article/10.1007/s12011-023-03818-6 [2] https://www.nature.com/articles/s41586-026-10821-z [3] https://www.uniprot.org/uniprotkb/P16455/entry

by Noaidi

7/30/2026 at 3:35:55 PM

That would imply that red meat eaters would be less likely to get cancer which doesn't seem to be the case. I'm not saying that zinc isn't a factor, but I think that saying a blanket "Zinc is needed to prevent cancer" is irresponsible. We should be so lucky that we can narrow it down to a single dietary element or be able to blame it simply upon nutrition.

by SketchySeaBeast

7/30/2026 at 3:49:34 PM

That’s not how statistical implication works… Learn about sufficient condition vs required condition before you start criticizing people. Taking zinc and smoking cigarettes still increases your chances of cancer, for example.

by kelipso

7/30/2026 at 3:59:14 PM

I understand that entirely. I'm saying that the way that GP is presenting their information it sounds like a "one neat trick", which of course it isn't because nothing ever is, which you and I are in agreement upon.

by SketchySeaBeast

7/30/2026 at 3:44:48 PM

[dead]

by aaron695

7/30/2026 at 3:45:44 PM

As a millennial growing up it was beaten into our head that smoking was a death sentence. I recently looked up what the actual cancer rate among smokers was... about 125k people in the US die of lung cancer annual. 25 million people smoke annually. That is a 0.5% chance for occasional smokers. Even if you smoke a pack a day your entire life, the cancer rate is less than 15%.

I am in no way saying it is okay to smoke, there are obviously other health risks associated with it... but researching that made me feel much better about that one pack a year I buy for vacation.

by crims0n

7/30/2026 at 3:50:39 PM

And that 125k includes people who don't smoke and never have. Sometimes the DNA in a single cell just gets fucked up in just the right way to cause cancer. Smoking just increases the odds.

by wpm

7/30/2026 at 4:12:17 PM

Cancer is not the only complication...

by dblohm7

7/30/2026 at 4:23:17 PM

Exactly. Hypertension, emphysema, people who don't smoke not wanting to be anywhere near you,

by gdulli

7/30/2026 at 3:55:19 PM

The actual infection rates for some STIs are also similarly low, per-encounter. But they are high enough that if you are promiscuous and have a large number of at-risk encounters then you will eventually get a bad roll of the dice.

by pdntspa