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

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.

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.

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.

In mice

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

6 months since i quit using nic gums.

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.

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.

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

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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.