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Tobacco Smoking & Cancer: How Does It Work?
The Ender
Registered User regular
Registered User regular
This is mostly for the sake of my own curiosity:
How does smoking actually cause lung and/or bladder cancer? What is the mechanism behind tobacco's ability to produce cancerous cells?
How does smoking actually cause lung and/or bladder cancer? What is the mechanism behind tobacco's ability to produce cancerous cells?
With Love and Courage
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You can read more here:
http://en.wikipedia.org/wiki/Tobacco
http://en.wikipedia.org/wiki/Health_effects_of_tobacco
The chemicals in tobacco smoke are very good at messing up your DNA. Cancer is basically just the DNA of some cells being messed up, causing them to reproduce uncontrollably into a tumor. Inhaling the carcinogens in tobacco into your inside parts (mouth, throat, lungs) exposes your more vulnerable bits to these toxins much more directly than you normally would.
All of that is a WAY over simplified summary, but there you go.
When cells are damaged and die and are replaced. Every time they are replaced, there is a chance of a mutation manifesting in the newly created cell. Tobacco smoke has the unfortunate effect of both increasing the rate at which cells are damaged and replaced, as well as directly damaging the DNA and increasing the probability of a mutation directly.
So, the more cells damage/die, the more often they are replaced, increasing rate at which they are replaced increases the probability over a period of time that one of the new cells will carry a mutation that could be considered cancerous. If there is a 1 in 1,000 chance a cell has a mutation, and instead of lasting a week, the cell only lasts a day, or a half day you're simply rolling the cancer dice much more vigorously. (figures are an example, no absolute accuracy intended).
Since smoking can damage the DNA of the cells directly, you go from a hypothetical 1 in 1,000 chance to say, a 1 in 500 chance. 1 in 1,000 once a week, vs 1 in 500 several times a week. You're increasing your risk.
Cancer can spread through the lymph system as well as circulatory system. It's sometimes easiest to think of them as mushrooms that can spore and break up as much as tumors. When they get to an advanced stage, they metastasize and spread through the body. So while the you may have a tumor on your liver, it is still being formed by the originating cancer. The lymph system is very efficient at it's role in the immune system, unfortunately in the case of cancer it means it can function as a subway system to lots of places in the body.
For interesting stuff on the lymph system and how we try to protect people exposed to certain radioactive materials, look in to how we use stable iodine to essentially "fill up" the lymph nodes with stable non radioactive iodine, so that when exposed to iodine-131 (which is radioactive) they are just too saturated to absorb and hold on to it.
Edit:
It should be noted that after a period of time the cancer rate of an ex smoker gets to nearly that of someone who has never smoked before. However, the big damage to the blood vessels doesn't go away. The elasticity decreases and you end out with rigid straws that don't dilate to meet the blood and oxygen demands of the body, causing things like COPD, COLD, Pulmonary Hypertension and generally poor coronary blood flow... all of which is bad.
Edit2: I am sure someone can correct me on some of that, it's just what I recall from some recent reading and such.
The really abbreviated story is that we don't really understand, but smoking is pretty convincingly linked to increased risk of pretty much everything bad (cancer of many varieties, strokes, cardiac problems, kidney problems, skin problems, etc.). Interestingly enough, secondhand smoke exposure is also linked to an increased risk of a lot of things, including cancer, but a different set of bad things than primary exposure.
I did a whole bunch of work with some of the proteins involved in programmed cell death for research I helped with in college, and it's a very interesting study. If I ever decide to go to graduate school it will probably be to study that.
Cancer is complicated, y'all.
Yep... if you hear someone use the phrase "a cure for cancer" they probably don't know anything about it and have even less idea how to go about making it happen.
It get's real tricky to explain cancer isn't really something that can be "cured" because of the way people view illness. You have an infection, you take antibiotics, you don't have an infection anymore. Folks expect this to be the way you also treat cancer. Leukemia is a good example of why it doesn't work that way. Chemo and Radiation Therapy are essentially the nuclear option (no pun!). You decimate all cells in the hopes that you can recover normal cellular activity after what could be considered a sort of reboot.
Old drugs like mustine (as in, mustard gas) and arsphenamine (as in arsenic) are terrifying but sort of a credit to medical science in their ability to see utility and treatment in the strangest places.
Ya this generalization does damage on it's own too, you always have the people doing the, well why haven't they cured it yet, folks.
When it truth, a couple 100 types of cancer have been "cured" , the problem is there's still 1000's to go with new versions popping up every day
There's also the big issue that the cancer tumour is pretty much just the end stage in a sequence of 10-20 mutations, a lot of the neighbouring cells will come from the same lineage as the cell that turns into a tumour but are behaving more or less normally with only 9-19 of the mutations. It's why cancer survival is usually presented as a 5 year survival rate - not only are most sufferers fairly old but you could wipe out every single tumour cell and still have a reoccurance later down the line when one of those cells that's just on the edge of becoming cancerous experiences that final mutation.