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Chromosome sizes in humans

  1. May 13, 2005 #1
    The p53 gene which is damaged or missing in many cases of cancer
    is located on chromosome 17 which is one of the smaller chromosomes?
    Does the size of chromosome 17 make it easier/more difficult
    for p53 to be damaged/removed?
    Do chromosomes respond to ultrasound?
    Could a damaged chromosome 17 be destroyed in cancer cells by ultrasound?
  2. jcsd
  3. May 14, 2005 #2
    the size of the chromosome does play a role, since during cell division a translocation can occur, where a piece of a chromosome breaks off and winds up stuck on another chromosome. this can result in altered expression of a gene, or overexpression.

    downs syndrome, for example, is caused by have 3 copies of chromosome 21. but sometimes a piece of chromosome 21 will break off and stick to chromosome 14 (a translocation) thus giving trisomy in effect, even though there are technically the correct number of chromosomes.

    trisomy or translocation of most chromosomes results in cell death. 21 is also a smaller chromosome, in fact i believe it is the smallest. so as radical of a change such as chromosomal defect is, it could possibly allow survival of the organism by virtual of the fact that the chromosome is small.

    keep in mind, that none of this may apply to a cancer cell...it depends on how that cell became cancerous. what we call "cancer" is molecularly a collection of at least several hundred different diseases. many forms of cancer do not rely on p53 at all.

    ultrasound is not something that will work, a covalent bond of a biomolecule is not going to be broken by something like ultrasound, unless it was a massive amount of energy in which case the cell, and neighboring cells, will long be dead by that time.

    also, to date, something like ultrasound is not specific enough. cytotoxic drugs, as terrible as they are, are more specific than ultrasound would ever be. acoustic waves simply propogate through the air too widely, targeted radiation is usually of much higher wavelength in order to try to "narrow the beam" and yet deliver enough energy for cytotoxicity.
    Last edited: May 14, 2005
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