Let’s say someone is a cigarette smoker. Each time they light a cigarette, are they chancing the fact that it could contain the carcinogen that will start the cancer that will be an issue for them years later, or is it a gradual build up of carcinogens in the body eventually causing lung cancer? Like, could the hypothetical hot dog I’m eating right now be responsible for cancer years down the line?
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There is no way to know.
The correlation between cancer and cigarettes is statistical. If you smoke many cigarettes you are more likely to get cancer than if you don’t. It’s not like “these 3 cigarettes” were the lucky ones (unlucky ones?) that gave you cancer.
Cancer susceptibility is a function of genetics and the whole life of environment you’ve experienced.
A carcinogen is in every cigarette. If it causes the bad type of damage or not is random.
Cancer happens when a cell is damaged in a very specific way. It’s growth control must break, it’s self-destruct must break, and it must still be considered a healthy cell by your immune system.
Each time a cell is exposed to a carcinogen it causes random damages. But if only one or two of the things are true the cell will just die and be replaced by a healthy cell. But if all these things happen you have a cell that grows out of control and your immune system doesn’t recognize it as problematic I.E. a tumor grows.
So the more you’re exposed to carcinogens the higher the chance that something bad happens somewhere.
At each point of cell devision a cell performs checks to ensure that all the DNA is still good and the cell is still capable of performing this function. If it fails these checks then the cell undergoes apoptosis or cell death.
However if those checks fail then the unhealthy cell reproduces and passes down its damaged mutations. If that mutation causes the signal to reproduce to remain on then you have a cancerous cell. (This is not ALWAYS a error in the go signal, some cells reproduce in response to deficiencies or injuries so sometimes it is an error in detecting these situations.)
Carcinogen is just a generic term for “any mutagen that can cause cancer-causing mutations.” And just because you have a cell with the cancer-causing mutation does not mean you will get cancer. Your body has specialized immune cells designed to hunt and kill cells that are not functioning correctly either due to mutations or viral infections and they tend to find cancer cells pretty quickly before they can reproduce, it is only when those cells reproduce to the point where the natural killer cells cannot remove them faster than they reproduce that tumors form.
Biologist here, and my answer is similar to Luckbot’s.
All cigarettes have carcinogens. Carcinogens causes damages to cells, specifically to their DNA, which is like the blueprint for creating proteins. Some types of damage in particular regions of the cell’s DNA can cause unregulated growth and division (cancer). Organisms have a bunch of checkpoints that check for damaged DNA to prevent damaged DNA from being replicated and creating more cells with the same damaged DNA. When those checkpoints fail and that compromised cell divides, that’s when you risk cancer.
So, in general, all cigarettes have carcinogens that can damage DNA in cells. However, not every damaging incident will cause cancer. But the more you smoke, the more times you take that risk, and the more likely you are to develop cancer. Same for your hot dog—there’s a chance, but you’ll probably be fine, unless you eat a ridiculous amount of hot dogs. There are tons and tons of known carcinogens, you can’t avoid them all. All you can do is avoid taking unnecessary risks. UV light, aka the sun’s rays, is also a carcinogen. It damages DNA. That’s why it’s a bad idea to use tanning beds, and why you should wear sunblock when you’re going to be in the sun for extended periods of time. We can’t realistically avoid all UV radiation, but you have a far lesser chance of developing skin cancer if you wear sunblock and don’t lay in UV tanning beds.
My epidemiologist wife explained it to me (an engineer) so i think i can do a good ELI5 explanation.
Cells will naturally self destruct over time. Just a part of life and they are replaced by new cells.
Mitosis causes cell division. Every time that occurs, you chance making a cell without the ability to self destruct. That cell can still reproduce (mitosis) and now it makes more cells without the ability to self destruct.
Certain things (some known, some unknown) causes mitosis to occur more often. Smoking damages lung cells and causes more mitosis to replace those damaged cells.
The more frequent the mitosis, the more likely that eventually you make a cell that cannot self destruct. Those cells are cancer cells.
Apologies to the biologists if I just made your head explode by oversimplifying it.
Every time a cell dies it is replaced. This happens million of times in our body.
When it is replaced the new cell can have an error. But first of al, a cell with an error may just not work and die. If the wrong cell survive it’s “first day”, your body will send antibodies to kill it.
You need a special combination in the error to make a cell that replicates faster than what your body can fight. We call it cancer. But not all the cancer are lethal the same way, some just grow a bit and stop.
The chances to get a cancer do increase if the cells have to be replaced too often, like getting a sunburn every day will force your skin to make new skin cells at a very very high rhythm.
Then there is how dirty is the copy of the cell. If the cell is exposed to toxic material or radiation during the copy, the chance of an error is increased.
To summarize, there is a big chunk of luck into surviving or not this mutation, but on average, smoking, drinking alcohol, getting sunburn, having a awful diet, all contribute to make this errors in the cells more likely.
I replied already for how it works.
I add CHANCES:
While poisoning has a safe limit, so as long as you limit the dose you have no long term effect, cancer has no safe dose.
You can live a perfect life and get a cancer anyway.
There is no lethal dose either, you may survive enormous doses.
The reason is your dna is a code, each person has a different code. Some codes are “lucky” just by chance; you can mix the code forever and no combination becomes a cancer. But you may have a very unlucky code to start with.
That’s why a medic would tell you “don’t smoke”, there is no safe amount.
Last thing to say is that there is a body resistance factor. Our antibodies do kill cancer cells. The problem is that this system is already busy all day, so don’t play with it or give it extra work. You are protected all day long, but pollution, diet, cosmic rays, uv, they are all trying to damage you all day long too.
The way atleast I understand it is cancer is caused by cells not dying properly. There is a small chance that a cell can become a cancer cell and you increase the odds by killing more cells than necessary. That’s why kids can get cancer.
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