Only 3 - 5 % of cancer cells in a tumor act cancerous

Discussion in 'Health and medical' started by Roger, Mar 12, 2004.

  1. Roger

    Roger Guest

    At least according to the article below. Seems to
    completely change the approach to dealing with cancer since
    the cancer stem cells don't have a life cycle like
    cancerous non-stem cells.

    Roger

    ------

    http://virtualtrials.com/news3.cfm?item=2410

    March 11, 2004

    Stem Cells in Tumors May Help Explain Some Cancer Mysteries

    If anyone still has doubts that the 1950s are a bygone era,
    consider some experiments scientists conducted then without
    raising eyebrows (let alone lawsuits).

    To probe the basics of cancer, a team of scientists injected
    cells from patients' colon, lung, ovarian and other tumors
    into the patients' own thighs. After trying this with
    varying numbers of cells, the scientists found that the
    transplants regenerated a tumor in the thigh (or in a mouse)
    only if at least one million cells were injected.

    If the bioethics of the 1950s fell short of today's, the
    science was a harbinger of an upheaval now shaking cancer
    biology. After going nowhere for decades, those old results
    have finally led to a revolutionary insight.

    "Within a tumor mass, there is only a small population of
    cells that can spawn more tumor; other cells in the tumor
    can't," says cancer biologist Robert Weinberg of the
    Whitehead Institute, Cambridge, Mass., who discovered the
    first human oncogene.

    The existence of these "tumor stem cells" promises to
    explain one of the more perplexing, and tragic, mysteries of
    cancer treatment. Biologists have made great strides in
    identifying molecular pathways by which cancer cells grow
    and spread. But although Iressa shrinks non-small-cell lung
    cancers, Erbitux shrinks advanced colorectal cancers and the
    just-approved Avastin shrinks metastatic colorectal cancer
    -- in each case, in only some patients -- the drugs prolong
    survival by mere months or not at all.

    The reason, says Dr. Weinberg, may be that "killing off the
    majority of cells in a tumor will still leave it with the
    ability to regenerate another tumor, from these stem cells."

    Eradicating the non-stem cells in a tumor "may result in a
    remission" and even the appearance of being cancer-free,
    explains molecular biologist John Dick of the University of
    Toronto, but "the disease will relapse if the tumor-
    initiating cells are not eliminated."

    Discovering that only some cancer cells are able to generate
    more tumor has been a struggle, as the lag between those
    1950s experiments and today shows.

    "The idea of cancer stem cells has been around for a long
    time," says biologist Irving Weissman of Stanford
    University. But no stem cell (normal or cancerous) had been
    isolated until he and his colleagues identified blood-
    forming stem cells in mice in 1987, and in humans in 1992.
    Seizing on this method for differentiating stem cells from
    others, Dr. Dick and his team discovered in 1994 that, in
    leukemia, only some cells have the ability to spawn more
    tumor. The Toronto team dubbed them "leukemic stem cells."

    It was an uphill struggle to figure out whether blood
    cancers are unique, or whether solid tumors have cancer stem
    cells, too. But after begging the university for a crucial
    $500,000 machine, biologists led by Michael Clarke and
    Muhammad Al-Hajj of the University of Michigan, Ann Arbor,
    found last year that breast cancer consists of a few cancer-
    initiating cells that can make more breast-cancer cells,
    seemingly forever, surrounded by an ocean of noncancer-
    initiating cells.

    Although the two kinds of cells looked identical, on closer
    inspection there were several "markers" -- think of them as
    microscopic flags poking up from the cell's surface -- that
    distinguish a breast-cancer stem cell from the cells in a
    breast tumor that can't generate more tumor. When the
    Michigan team injected as few as 100 cells of the former
    into mice, breast tumors grew every time. Not even tens of
    thousands of noncancer stem cells produced a tumor. Since
    the Michigan discovery, researchers in Japan and Canada have
    found brain-cancer stem cells; stem cells likely exist in
    other solid tumors, too.

    Dr. Clarke estimates that breast cancer stem cells make up
    as little as 3% to 5% of some tumors. That's the good
    news. Those are the only cells you have to kill to cure
    cancer, because non-stem cells eventually die off on
    their own. Even when non-stem cells spread, they don't
    pose much danger because they die after dividing a few
    times. The goal of current chemotherapy, to kill as many
    cells as possible, can probably be dialed back.

    The bad news is that standard chemo hits tumor cells at a
    vulnerable point in their life cycle, but cancer stem cells
    don't seem to cycle this way. "I think the reason cancer
    therapy does not cure all cancers has to do with the unique
    properties" of the cancer stem cell, says Dr. Dick.

    Ever more sobering, the molecular pathways that scientists
    have recently identified, with much fanfare, as allowing
    cancer cells to grow may not be critical after all. If such
    a pathway promotes growth in the zillions of cells that are
    not cancer stem cells, it may be inconsequential. The only
    pathways that matter are those that keep the miscreants
    alive and thriving. Or as Dr. Weinberg told me, "tumor stem
    cells may explain why you can have tumor shrinkage but not
    life extension. If current chemotherapies don't target tumor
    stem cells, the cells keep making more tumor."

    On the bright side, knowing which cells they have to kill
    gives scientists a better shot at finding therapies that
    do that. "I'm optimistic we can figure this out," says
    Dr. Clarke.
     
    Tags:


  2. Steph

    Steph Guest

    "Roger" <[email protected]> wrote in message
    news:[email protected]...
    > At least according to the article below. Seems to
    > completely change the approach to dealing with cancer
    > since the cancer stem cells don't have a life cycle like
    > cancerous non-stem cells.
    >
    > Roger
    >

    It's been well established for 30 years that only a small
    proportion of the cells in a cancer are able to continually
    divide and spread. In many sarcomas, the Cell Loss Factor is
    as high as 99% So this is nothing new, and nothing useful
     
  3. Roger

    Roger Guest

    "Steph" <[email protected]> wrote in message
    news:[email protected]...
    >
    > "Roger" <[email protected]> wrote in message news:O3d4c.345-
    > [email protected]
    > > At least according to the article below. Seems to
    > > completely change the approach to dealing with cancer
    > > since the cancer stem cells don't have a life cycle like
    > > cancerous non-stem cells.
    > >
    > > Roger
    > >
    >
    > It's been well established for 30 years that only a small
    > proportion of
    the
    > cells in a cancer are able to continually divide and
    > spread. In many sarcomas, the Cell Loss Factor is as high
    > as 99% So this is nothing new, and nothing useful

    The findings about the existence of the cancer stem cells
    appear to be new. The fact that they have a different
    life cycle than "harmless" cancer cells appears to be
    new. As for the findings being not useful, well maybe not
    yet. But I think this is a necessary step to move to the
    next step (targeting treatments at the cancer stem cells)
    so in the end I think it will be not only useful but a
    necessary finding.

    Roger
     
  4. Steph

    Steph Guest

    "Roger" <[email protected]> wrote in message
    news:[email protected]...
    >
    > "Steph" <[email protected]> wrote in message
    > news:[email protected]...
    > >
    > > "Roger" <[email protected]> wrote in message news:O3d4c.3-
    > > [email protected]
    > > > At least according to the article below. Seems to
    > > > completely change
    the
    > > > approach to dealing with cancer since the cancer stem
    > > > cells don't have
    a
    > > > life cycle like cancerous non-stem cells.
    > > >
    > > > Roger
    > > >
    > >
    > > It's been well established for 30 years that only a
    > > small proportion of
    > the
    > > cells in a cancer are able to continually divide and
    > > spread. In many sarcomas, the Cell Loss Factor is as
    > > high as 99% So this is nothing new, and nothing useful
    >
    > The findings about the existence of the cancer stem cells
    > appear to be
    new.
    > The fact that they have a different life cycle than
    > "harmless" cancer
    cells
    > appears to be new. As for the findings being not useful,
    > well maybe not yet. But I think this is a necessary step
    > to move to the next step (targeting treatments at the
    > cancer stem cells) so in the end I think it will be not
    > only useful but a necessary finding.
    >
    > Roger
    >

    There is no such thing as a "cancer stem cell" There are
    cells in a cancer which can't divide, many which can only
    divide a few times, then die, and a small proportion of
    cells which are "immortal" - I guess this is what you mean.
    But that is not new knowledge. The only cells likely to kill
    you are the immortal ones, and these are the cells targeted
    by radiation and chemo. The only cells responsible for
    recurrence are the immortal ones. The only real cancer cells
    are the immortal ones..................
     
  5. Roger

    Roger Guest

    "Steph" <[email protected]> wrote in message
    news:[email protected]...
    >
    > "Roger" <[email protected]> wrote in message news:0yd4c.345-
    > [email protected]
    > >
    > > "Steph" <[email protected]> wrote in message
    > > news:[email protected]...
    > > >
    > > > "Roger" <[email protected]> wrote in message news:O3d4c-
    > > > [email protected]
    > > > > At least according to the article below. Seems to
    > > > > completely change
    > the
    > > > > approach to dealing with cancer since the cancer
    > > > > stem cells don't
    have
    > a
    > > > > life cycle like cancerous non-stem cells.
    > > > >
    > > > > Roger
    > > > >
    > > >
    > > > It's been well established for 30 years that only a
    > > > small proportion
    of
    > > the
    > > > cells in a cancer are able to continually divide and
    > > > spread. In many sarcomas, the Cell Loss Factor is as
    > > > high as 99% So this is nothing new, and nothing useful

    What is new is the isolation of these cells. It may have
    been known before that there was a subset of such cells but
    it's only recently that the stem cell-like cancer cells in a
    human breast cancer were isolated from the other cancer
    cells and tested on mice. So this is new. It's why it was in
    the Proceedings of the National Academy of Sciences in 2003.

    And it's a breakthrough because these cells can be examined
    closely to see what is unique about them. If they are
    somewhat uniform, then it makes the job of finding effective
    therapies a lot easier compared to having to deal with a
    hundred (or whatever) radically different types of cancer
    cells due to mutations.

    > >
    > > The findings about the existence of the cancer stem
    > > cells appear to be
    > new.
    > > The fact that they have a different life cycle than
    > > "harmless" cancer
    > cells
    > > appears to be new. As for the findings being not useful,
    > > well maybe not yet. But I think this is a necessary step
    > > to move to the next step (targeting treatments at the
    > > cancer stem cells) so in the end I think it will be not
    > > only useful but a necessary finding.
    > >
    > > Roger
    > >
    >
    > There is no such thing as a "cancer stem cell"

    According to the researcher (Michael Clarke of the
    University of Michigan) who discovered last year the subset
    of breast cancer cells in a breast cancer tumor that act
    genuinely cancerous, these cells are stem cells in the sense
    that all cancer cells come from them. So these cancer stem
    cells produce daughter cancer stem cells as well as less
    dangerous cancer cells that are not cancer stem cells. Thus
    they play a role similar to normal stem cells in that all
    cells come from stem cells.

    > There are cells in a cancer which can't divide, many which
    > can only divide
    a
    > few times, then die, and a small proportion of cells
    > which are
    "immortal" -
    > I guess this is what you mean. But that is not new
    > knowledge.

    But what's new is the isolation of them and the testing of
    them in mice. The testing consisted of putting 100 of these
    cancer stem cells in the mice and a tumor would grow.
    Normally 100 cancer cells can not produce a tumor - about
    one million are needed. They also tested the non-stem cell
    cancer cells and none of them could produce a tumor no
    matter how many were injected into the mice.

    Thus all the mutations those cancer cells have undergone do
    not matter. This is why (if I understand this correctly)
    this discovery has the potential to make it a lot easier to
    kill a tumor. Now they can zero in on just those cells since
    they have them isolated now and see what will prevent them
    from making daughter cells and what will kill them.

    Roger

    The only cells
    > likely to kill you are the immortal ones, and these are
    > the cells targeted by radiation and chemo. The only cells
    > responsible for recurrence are the immortal ones. The only
    > real cancer cells are the immortal ones..................
     
  6. Steph

    Steph Guest

  7. Madiba

    Madiba Guest

    Steph <[email protected]> wrote:

    > "Roger" <[email protected]> wrote in message news:peB4c.361-
    > [email protected]
    > >
    >
    > I've been in this game long enough to know you shouldn't
    > hold your breath............
    . :-/

    Speaking of which, you must be blue in the face waiting for
    that beer I owe you.. Now if you happen to be in Scotland
    again during the last week of March... (3 consultant posts
    up for grabs at the Beatson) you could breath easier again
    and enjoy a Kilkenny with us. If not, hold thumbs please..
    --
    Jon
     
  8. Steph

    Steph Guest

    "madiba" <[email protected]> wrote in message
    news:1gap9zf.1sxj4nm1gjhgjlN%[email protected]...
    > Steph <[email protected]> wrote:
    >
    > > "Roger" <[email protected]> wrote in message news:peB4c.3-
    > > [email protected]
    > > >
    > >
    > > I've been in this game long enough to know you shouldn't
    > > hold your breath............
    > . :-/
    >
    > Speaking of which, you must be blue in the face waiting
    > for that beer I owe you.. Now if you happen to be in
    > Scotland again during the last week of March... (3
    > consultant posts up for grabs at the Beatson) you could
    > breath easier again and enjoy a Kilkenny with us. If not,
    > hold thumbs please..
    > --
    > Jon

    That's 9 consultant posts up for grabs at the Beatson,
    Jon...........though they are only advertising 3 at a time.
    In fact, I'll let you into a secret...........I was
    "invited" to apply for the post of Director but when they
    saw my set of proposals for turning the place around, they
    decided not to short list me..... Was in the UK in Feb, and
    won't be back until next year sometime. Not thinking of a
    move to Bonny Scotland yourself, are you?

    Don't worry, the pint is in my PalmPilot spreadsheet......
     
  9. Madiba

    Madiba Guest

    Steph <[email protected]> wrote:

    > "madiba" <[email protected]> wrote in message
    > news:1gap9zf.1sxj4nm1gjhgjlN%[email protected]...
    > > Steph <[email protected]> wrote:
    > >
    > > > "Roger" <[email protected]> wrote in message news:peB4c-
    > > > [email protected]
    > > > >
    > > >
    > > > I've been in this game long enough to know you
    > > > shouldn't hold your breath............
    > > . :-/
    > >
    > > Speaking of which, you must be blue in the face waiting
    > > for that beer I owe you.. Now if you happen to be in
    > > Scotland again during the last week of March... (3
    > > consultant posts up for grabs at the Beatson) you could
    > > breath easier again and enjoy a Kilkenny with us. If
    > > not, hold thumbs please..
    >
    > That's 9 consultant posts up for grabs at the Beatson,
    > Jon...........though they are only advertising 3 at a
    > time. In fact, I'll let you into a secret...........I was
    > "invited" to apply for the post of Director but when they
    > saw my set of proposals for turning the place around, they
    > decided not to short list me..... Was in the UK in Feb,
    > and won't be back until next year sometime. Not thinking
    > of a move to Bonny Scotland yourself, are you?
    I was, but if that means carring the workload of the missing
    6 perhaps I should reconsider.. Prefer warmer climes
    normally so Portsmouth was where I aimed for - but a cute
    Finn beat me to the finish.
    --
    Jon
     
  10. Steph

    Steph Guest

    "madiba" <[email protected]> wrote in message
    news:1gar2my.11d896w1h77vasN%[email protected]...
    > Steph <[email protected]> wrote:
    >
    > > "madiba" <[email protected]> wrote in message
    > > news:1gap9zf.1sxj4nm1gjhgjlN%[email protected]...
    > > > Steph <[email protected]> wrote:
    > > >
    > > > > "Roger" <[email protected]> wrote in message news:peB-
    > > > > [email protected]
    > > > > ...
    > > > > >
    > > > >
    > > > > I've been in this game long enough to know you
    > > > > shouldn't hold your breath............
    > > > . :-/
    > > >
    > > > Speaking of which, you must be blue in the face
    > > > waiting for that beer
    I
    > > > owe you.. Now if you happen to be in Scotland again
    > > > during the last week of March... (3 consultant posts
    > > > up for grabs at the Beatson) you could breath easier
    > > > again and enjoy a Kilkenny with us. If not, hold
    > > > thumbs please..
    > >
    > > That's 9 consultant posts up for grabs at the Beatson,
    Jon...........though
    > > they are only advertising 3 at a time. In fact, I'll let
    > > you into a secret...........I was "invited" to apply
    for
    > > the post of Director but when they saw my set of
    > > proposals for turning
    the
    > > place around, they decided not to short list me..... Was
    > > in the UK in Feb, and won't be back until next year
    > > sometime. Not thinking of a move to Bonny Scotland
    > > yourself, are you?
    > I was, but if that means carring the workload of the
    > missing 6 perhaps I should reconsider.. Prefer warmer
    > climes normally so Portsmouth was where I aimed for - but
    > a cute Finn beat me to the finish.
    > --
    > Jon
    No shortage of Clinical Oncology jobs in the BMJ. There are
    about 60+ unfilled consultant posts in the UK
     
  11. Dr Chaos

    Dr Chaos Guest

    On Fri, 12 Mar 2004 16:03:52 GMT, Steph <[email protected]> wrote:
    >
    > "Roger" <[email protected]> wrote in message news:0yd4c.345-
    > [email protected]
    >>
    >> "Steph" <[email protected]> wrote in message
    >> news:[email protected]...
    >> >
    >> > "Roger" <[email protected]> wrote in message news:O3d4c.-
    >> > [email protected]
    >> > > At least according to the article below. Seems to
    >> > > completely change
    > the
    >> > > approach to dealing with cancer since the cancer stem
    >> > > cells don't have
    > a
    >> > > life cycle like cancerous non-stem cells.
    >> > >
    >> > > Roger
    >> > >
    >> >
    >> > It's been well established for 30 years that only a
    >> > small proportion of
    >> the
    >> > cells in a cancer are able to continually divide and
    >> > spread. In many sarcomas, the Cell Loss Factor is as
    >> > high as 99% So this is nothing new, and nothing useful
    >>
    >> The findings about the existence of the cancer stem cells
    >> appear to be
    > new.
    >> The fact that they have a different life cycle than
    >> "harmless" cancer
    > cells
    >> appears to be new. As for the findings being not useful,
    >> well maybe not yet. But I think this is a necessary step
    >> to move to the next step (targeting treatments at the
    >> cancer stem cells) so in the end I think it will be not
    >> only useful but a necessary finding.
    >>
    >> Roger
    >>
    >
    > There is no such thing as a "cancer stem cell" There are
    > cells in a cancer which can't divide, many which can only
    > divide a few times, then die, and a small proportion of
    > cells which are "immortal" - I guess this is what you
    > mean. But that is not new knowledge. The only cells likely
    > to kill you are the immortal ones, and these are the cells
    > targeted by radiation and chemo. The only cells
    > responsible for recurrence are the immortal ones. The only
    > real cancer cells are the immortal ones..................

    And do the assays for drug activity differentiate between
    the 'immortal' ones and the others?

    I would tend to doubt so, and this means that many of the
    treatment strategies might be going against the wrong cell
    populations.
     
  12. Steph

    Steph Guest

    "Dr Chaos" <[email protected]> wrote in message
    news:[email protected]...
    > On Fri, 12 Mar 2004 16:03:52 GMT, Steph
    > <[email protected]> wrote:
    > >
    > > "Roger" <[email protected]> wrote in message news:0yd4c.3-
    > > [email protected]
    > >>
    > >> "Steph" <[email protected]> wrote in message
    > >> news:[email protected]...
    > >> >
    > >> > "Roger" <[email protected]> wrote in message news:O3d4-
    > >> > [email protected]
    > >> > > At least according to the article below. Seems to
    > >> > > completely
    change
    > > the
    > >> > > approach to dealing with cancer since the cancer
    > >> > > stem cells don't
    have
    > > a
    > >> > > life cycle like cancerous non-stem cells.
    > >> > >
    > >> > > Roger
    > >> > >
    > >> >
    > >> > It's been well established for 30 years that only a
    > >> > small proportion
    of
    > >> the
    > >> > cells in a cancer are able to continually divide and
    > >> > spread. In many sarcomas, the Cell Loss Factor is as
    > >> > high as 99% So this is nothing new, and nothing
    > >> > useful
    > >>
    > >> The findings about the existence of the cancer stem
    > >> cells appear to be
    > > new.
    > >> The fact that they have a different life cycle than
    > >> "harmless" cancer
    > > cells
    > >> appears to be new. As for the findings being not
    > >> useful, well maybe
    not
    > >> yet. But I think this is a necessary step to move to
    > >> the next step (targeting treatments at the cancer stem
    > >> cells) so in the end I think
    it
    > >> will be not only useful but a necessary finding.
    > >>
    > >> Roger
    > >>
    > >
    > > There is no such thing as a "cancer stem cell" There
    > > are cells in a cancer which can't divide, many which
    > > can only
    divide a
    > > few times, then die, and a small proportion of cells
    > > which are
    "immortal" -
    > > I guess this is what you mean. But that is not new
    > > knowledge. The only
    cells
    > > likely to kill you are the immortal ones, and these are
    > > the cells
    targeted
    > > by radiation and chemo. The only cells responsible for
    > > recurrence are
    the
    > > immortal ones. The only real cancer cells are the
    > > immortal ones..................
    >
    > And do the assays for drug activity differentiate between
    > the 'immortal' ones and the others?

    No. But the immortal ones ( clonogenic cells) for many
    cancers can be grown indefinitely in vitro. Ever heard of
    HeLa cells? Very commonly used for cancer experimentation,
    and all derived from a single cancer patient 20+ years ago.
    Still going strong.

    >
    > I would tend to doubt so, and this means that many of the
    > treatment strategies might be going against the wrong cell
    > populations.
    >

    Just because in vitro assays don't work doesn't mean that
    the clonogenic cells in a cancer aren't the culprits
     
  13. Dr Chaos

    Dr Chaos Guest

    On Wed, 07 Apr 2004 01:57:53 GMT, Steph <[email protected]> wrote:
    >
    > No. But the immortal ones ( clonogenic cells) for many
    > cancers can be grown indefinitely in vitro. Ever heard of
    > HeLa cells? Very commonly used for cancer experimentation,
    > and all derived from a single cancer patient 20+ years
    > ago. Still going strong.

    Good. Now what if they have characteristics unlike
    spontaneous human cancers? In particular the minority of
    human cancer stem cells.

    >>
    >> I would tend to doubt so, and this means that many of the
    >> treatment strategies might be going against the wrong
    >> cell populations.
    >>
    >
    > Just because in vitro assays don't work doesn't mean that
    > the clonogenic cells in a cancer aren't the culprits

    I think we're in agreement.

    I think that this new result actually is big news, and ought
    to seriously change the nature of cancer research.

    Tumor shrinkage means little if it shrinks the wrong 97% of
    the cell population.
     
  14. Steph

    Steph Guest

    "Dr Chaos" <[email protected]> wrote in message
    news:[email protected]...
    > On Wed, 07 Apr 2004 01:57:53 GMT, Steph
    > <[email protected]> wrote:
    > >
    > > No. But the immortal ones ( clonogenic cells) for many
    > > cancers can be grown indefinitely in vitro. Ever heard
    > > of HeLa cells? Very commonly used for cancer
    > > experimentation, and all derived from a single cancer
    > > patient 20+ years ago. Still going strong.
    >
    > Good. Now what if they have characteristics unlike
    > spontaneous human cancers? In particular the minority of
    > human cancer stem cells.
    >

    He La is a spontaneous human cancer cell line.........

    > >>
    > >> I would tend to doubt so, and this means that many of
    > >> the treatment strategies might be going against the
    > >> wrong cell populations.
    > >>
    > >
    > > Just because in vitro assays don't work doesn't mean
    > > that the clonogenic cells in a cancer aren't the
    > > culprits
    >
    > I think we're in agreement.
    >
    > I think that this new result actually is big news, and
    > ought to seriously change the nature of cancer research.
    >
    > Tumor shrinkage means little if it shrinks the wrong 97%
    > of the cell population.

    Sensible oncologist have known that (and been saying it) for
    years What is more, by the time a cancer is 1cm in size, it
    is 3/4 of the way to being 1kg in size............

    The "New result" isn't new, and isn't a result. Don't get
    too excited
     
  15. Dr Chaos

    Dr Chaos Guest

    On Sat, 10 Apr 2004 23:32:34 GMT, Steph <[email protected]> wrote:
    >> I think that this new result actually is big news, and
    >> ought to seriously change the nature of cancer research.
    >>
    >> Tumor shrinkage means little if it shrinks the wrong 97%
    >> of the cell population.
    >
    > Sensible oncologist have known that (and been saying it)
    > for years What is more, by the time a cancer is 1cm in
    > size, it is 3/4 of the way to being 1kg in
    > size............
    >
    > The "New result" isn't new, and isn't a result. Don't get
    > too excited

    The question is whether the therapies preferentially kill
    the 97% of the wrong cells, since they were probably assayed
    in drug development by tumor shrinkage.

    IF they had a way to assay "%age kill of tumor stem cells"
    perhaps the drugs would be far different.
     
  16. Steph

    Steph Guest

    "Dr Chaos" <[email protected]> wrote in message
    news:[email protected]...
    > On Sat, 10 Apr 2004 23:32:34 GMT, Steph
    > <[email protected]> wrote:
    > >> I think that this new result actually is big news, and
    > >> ought to seriously change the nature of cancer
    > >> research.
    > >>
    > >> Tumor shrinkage means little if it shrinks the wrong
    > >> 97% of the cell population.
    > >
    > > Sensible oncologist have known that (and been saying it)
    > > for years What is more, by the time a cancer is 1cm in
    > > size, it is 3/4 of the way
    to
    > > being 1kg in size............
    > >
    > > The "New result" isn't new, and isn't a result. Don't
    > > get too excited
    >
    > The question is whether the therapies preferentially kill
    > the 97% of the wrong cells, since they were probably
    > assayed in drug development by tumor shrinkage.
    >
    > IF they had a way to assay "%age kill of tumor stem cells"
    > perhaps the drugs would be far different.

    Paradoxically, it is actually the clonogenic cells (your
    stem cells) which are the most sensitive to radiation and
    chemotherapy.....
     
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