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  1. #26
    Big science. Hallelujah. noddin0ff's Avatar
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    A lot is known about what causes DNA mutations, and I could probably provide you with hundreds of references citing specific base mutations that predispose one to cancer. Here’s a link to a database who’s sole purpose is to catalog all the mutations found in a single protein named p53 (“p” for protein, 53 for the molecular weight in kDa).
    http://www-p53.iarc.fr/P53aim.html
    p53 mutations are associated with most cancers. p53 is often referred to as a tumor suppressor gene. The function of the normal protein seems to be to limit cell division. When it is damaged, cells may divide inappropriately. That is something that really predisposes a cell to begin to acquire further mutations that could make it cancerous.

    In 1993, p53 was labeled ‘Molecule of the Year’ by Science magazine.
    http://www.hhmi.org/annual95/b140.html

    However, cancers arise from the cumulative effect of many mutations in many genes. And different combinations of mutated genes may predispose one to different kinds of cancers in different tissues. In addition to single base mutations, large-scale chromosomal rearrangements as well as mitotic errors resulting in aneuploidy (too many chromosomes) also contribute to cancers. Every cancer is unique in the kinds of mutations that led to it, but many have similarities (such as p53 mutations).

    To evaluate a chemical for its potential as a mutagen the first thing people generally do is conduct an Ames Test
    http://www.sci.sdsu.edu/~smaloy/Micr...-sup/ames.html

    If you want to read about mutations you can try this link. It’s a thorough and concise introduction.
    http://www-personal.k-state.edu/~bethmont/mutdes.html

    No need to nominate me, this stuffs been know for many, many years.

    If you ingest Aspartame, your ingesting Aspartame. Sunshine is also known to cause cancer.

  2. #27
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    Sunshine is also known to cause cancer.
    My sentiments exactly.

    Your post although thoroughly informative to someone who has never studied life sciences, is level II BioChem. There are so many variables to consider when discussing cancerous mutations. Can you say for a fact that one gamma particle, x-ray or neutron cannot cause a cancerous mutation? Or a limited exposure to uv? My guess is no. Can you explain why soneone can smoke for their entire life and never develop cancer? I'm guessing no again.....pointless discussion. I don't need to resort to bombast to get my point across.

    A lot is known about what causes DNA mutations, and I could probably provide you with hundreds of references citing specific base mutations that predispose one to cancer.
    You're really missing the point in what i was trying to say.

    We's about done here?

    Wayne

  3. #28
    Big science. Hallelujah. noddin0ff's Avatar
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    Quote Originally Posted by wayner86
    I don't need to resort to bombast to get my point across.
    You could try clarity. What's your point?

  4. #29
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    I could probably provide you with hundreds of references citing specific base mutations that predispose one to cancer.
    What triggered these base mutations?

  5. #30
    Big science. Hallelujah. noddin0ff's Avatar
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    Quote Originally Posted by wayner86
    What triggered these base mutations?
    Honestly, it could be anything, including just existing. The normal cell processes of life cause DNA errors. Some people inherit mutations, some people are just unlucky. You start out as one cell and turn into an estimated 100 trillion cells. Each cell has more than 3.2 billion base pairs. I don't know off hand the error rate for DNA polymerase but I'm sure its worse than 1 error in 100 million bases. So (100 trillion x 3.2 billion)/100 million is still a lot of mutations. So even if you have nothing damaging your DNA, you'll still accumulate mutations just because you're multicellular through replication errors. Anyway my point is there's a natural background rate of mutation. If you live long enough, you will get cancer with statistical certainty.

    A cancer arises from a combination of mutations some of which you've may have had since conception and some you got along the way. Some estimates are that it takes about 7 mutations in key genes to yield a cancer counting the ones you may have been born with. Going from the cancer back to the cause is impossible, partially becuase by definition there are multiple contributing mutations. Thus, the only way you can link a potential chemical to potential carcinogenic effects is through things like the Ames test and by carefully studying the statistics of populations looking for correlations between people who drink a lot of diet sodas and people who get cancers, for example. Sure, at some level an Aspartame molecule may turn into that one formaldehyde molecule that made the one base mutation that made the cancer that kills you. But, research suggests that the odds of that are so small as to not be distinguishable from the background of all the other things that kill you.

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