Science for the day
Nature was kind of lame today, and I was too lazy to look in other journals. I have just two things, and the first isn't even from a journal--it's something I've picked up in the last year that I think everyone should know.
What is metastasis? Cells in a tumor may lose the proteins that are responsible for causing them to adhere to other cells. At that point, they're pretty much like, "See ya, dude," and take off for destinations unknown in the body. This is the main reason that cancer comes back even after successful treatment.
There are two basic categories of genes implicated in cancer, oncogenes (literally, cancer genes) and tumor suppressors.
Remember, humans have twenty-three chromosomes--and two versions of twenty-two of those (one from mom, one from dad). Women have two versions of the twenty-third chromosome (X) as well, but men have an X and a Y.
That means you have two copies of almost every gene. Exceptions include SRY, the gene that is endowed with the responsibility of, well, endowing men with their maleness. Yes, it's actually called SRY.
Two copies means you can lose one and be mostly okay--kind of like how you have two lungs, two testicles or ovaries, and two arms and legs.
--but only mostly. For some genes, loss of one copy causes severe mental retardation, for example.
And that's where tumor suppressors come into play. If you have a risky family history of cancer, it's probably because some of your ancestors (e.g., parents, grandparents, great-grandparents) have a broken tumor suppressor on one chromosome, and probably were born with it like that. This means only one working copy, making them far more prone through the course of regular genetic damage to break the other copy. Without that tumor suppressor, uncontrolled growth begins. The cell loses its ability to go, "Oh, crap, I'm broken. Self destruct!"
Of course, each of your kids only has aone in four fifty-percent chance of getting a broken tumor suppressor from you.
Oncogenes are the inverse of tumor suppressors. Like SRY, the body needs one or fewer copies of it. Cells that lack it might die, but that's the worst of it. You're likely to have two working copies of any given oncogene, but one is always turned off by various mechanisms we don't yet fully understand (or I don't).
A couple of things can go wrong with an oncogene. The mechanism which inactivates the oncogene could fail. Alternatively, the oncogene could mutate to a form that has much more activity than is normal; or it could be up-regulated by something else breaking (like a tumor suppressor).
When that happens, the signaling in the cell goes out of whack, and the cell again loses its ability to self-destruct.
Today there was an article published in the Boston Globe which mentioned the FDA is investigating drugs which suppress the TNFα receptor. Such drugs are used to treat auto-immune diseases like lupus, rheumatoid arthritis, and Crohn's.
TNFα stands for Tumor Necrosis Factor alpha. That means that it's implicated in tumors dying. I'd have to look up the original paper to find the exact circumstances, but I'd gather from the name that TNFα is a tumor suppressor which gets activated in situations where the body develops pre-cancerous tumors.
Thus, taking Remicade might make it a little more likely that a tumor will advance from pre-cancer to cancer. It's not an issue of the drug turning off the gene--instead the drug is blocking the action of the gene product, so it doesn't matter how many copies of it you've got.
It might even be that your auto-immune disease, if you have one, plays a role in protecting you from cancer; it keeps that tumor suppressor gene product active. (This is speculation. Actually, don't trust anything I write without doing some research of your own. I am not a legitimate source of medical advice.)
What can you do to protect yourself, whether you have a family history or not?
Avoid known carcinogens. I hear people say all the time, "Well, water is a carcinogen to an extent." This is a frame created by corporate America to make you shrug off warnings about BPA in your soda bottles. There's a difference between avoiding water and avoiding soda, and if you can't see it, you're probably not going to listen to any of my other advice, either.
Don't smoke cigarettes. Avoid deep-fried foods. Don't over-toast your bread. In general, you'll be healthier even if you don't develop cancer.
If you know you have a family history of skin cancer, that means you might be missing a copy of a tumor suppressor. Don't spend lots of time out in the sun.
Edit: I said that you have a one-in-four chance of passing a damaged germ-line tumor suppressor on to each child; this was incorrect. It's a one-in-two chance. Thanks to
ruthytoothy for pointing it out.
Tumors and Cancers
How can you have a non-cancerous tumor? Well, tumor actually just means lump or swelling, but in modern English we take it to mean neoplasm (I'll keep using tumor). A benign tumor is one that (1) does not grow at an uncontrolled rate, (2) does not invade other tissues, and (3) does not metastasize.What is metastasis? Cells in a tumor may lose the proteins that are responsible for causing them to adhere to other cells. At that point, they're pretty much like, "See ya, dude," and take off for destinations unknown in the body. This is the main reason that cancer comes back even after successful treatment.
There are two basic categories of genes implicated in cancer, oncogenes (literally, cancer genes) and tumor suppressors.
Remember, humans have twenty-three chromosomes--and two versions of twenty-two of those (one from mom, one from dad). Women have two versions of the twenty-third chromosome (X) as well, but men have an X and a Y.
That means you have two copies of almost every gene. Exceptions include SRY, the gene that is endowed with the responsibility of, well, endowing men with their maleness. Yes, it's actually called SRY.
Two copies means you can lose one and be mostly okay--kind of like how you have two lungs, two testicles or ovaries, and two arms and legs.
--but only mostly. For some genes, loss of one copy causes severe mental retardation, for example.
And that's where tumor suppressors come into play. If you have a risky family history of cancer, it's probably because some of your ancestors (e.g., parents, grandparents, great-grandparents) have a broken tumor suppressor on one chromosome, and probably were born with it like that. This means only one working copy, making them far more prone through the course of regular genetic damage to break the other copy. Without that tumor suppressor, uncontrolled growth begins. The cell loses its ability to go, "Oh, crap, I'm broken. Self destruct!"
Of course, each of your kids only has a
Oncogenes are the inverse of tumor suppressors. Like SRY, the body needs one or fewer copies of it. Cells that lack it might die, but that's the worst of it. You're likely to have two working copies of any given oncogene, but one is always turned off by various mechanisms we don't yet fully understand (or I don't).
A couple of things can go wrong with an oncogene. The mechanism which inactivates the oncogene could fail. Alternatively, the oncogene could mutate to a form that has much more activity than is normal; or it could be up-regulated by something else breaking (like a tumor suppressor).
When that happens, the signaling in the cell goes out of whack, and the cell again loses its ability to self-destruct.
Today there was an article published in the Boston Globe which mentioned the FDA is investigating drugs which suppress the TNFα receptor. Such drugs are used to treat auto-immune diseases like lupus, rheumatoid arthritis, and Crohn's.
TNFα stands for Tumor Necrosis Factor alpha. That means that it's implicated in tumors dying. I'd have to look up the original paper to find the exact circumstances, but I'd gather from the name that TNFα is a tumor suppressor which gets activated in situations where the body develops pre-cancerous tumors.
Thus, taking Remicade might make it a little more likely that a tumor will advance from pre-cancer to cancer. It's not an issue of the drug turning off the gene--instead the drug is blocking the action of the gene product, so it doesn't matter how many copies of it you've got.
It might even be that your auto-immune disease, if you have one, plays a role in protecting you from cancer; it keeps that tumor suppressor gene product active. (This is speculation. Actually, don't trust anything I write without doing some research of your own. I am not a legitimate source of medical advice.)
What can you do to protect yourself, whether you have a family history or not?
Avoid known carcinogens. I hear people say all the time, "Well, water is a carcinogen to an extent." This is a frame created by corporate America to make you shrug off warnings about BPA in your soda bottles. There's a difference between avoiding water and avoiding soda, and if you can't see it, you're probably not going to listen to any of my other advice, either.
Don't smoke cigarettes. Avoid deep-fried foods. Don't over-toast your bread. In general, you'll be healthier even if you don't develop cancer.
If you know you have a family history of skin cancer, that means you might be missing a copy of a tumor suppressor. Don't spend lots of time out in the sun.
Oxidation states
This is a bit geeky. Apparently, we were taught chemistry wrong. I don't really understand it, so maybe someone else will explain? It has to do with oxidation state not being linked to the charge on transition metals (we were all always taught that they are linked).Edit: I said that you have a one-in-four chance of passing a damaged germ-line tumor suppressor on to each child; this was incorrect. It's a one-in-two chance. Thanks to
ruthytoothy for pointing it out.