[tt] [extropy-chat] Arresting Stem Cells May Trump Tumor Shrinkage in Rating Cancer Treatments, Researcher Says

[Eugen Leitl]

----- Forwarded message from Robert Bradbury <robert.bradbury at gmail.com> -----

From: Robert Bradbury <robert.bradbury at gmail.com>
Date: Tue, 20 Mar 2007 12:30:40 +0000
To: ExI chat list <extropy-chat at lists.extropy.org>
Subject: Re: [extropy-chat] Arresting Stem Cells May Trump Tumor Shrinkage
	in Rating Cancer Treatments, Researcher Says
Reply-To: ExI chat list <extropy-chat at lists.extropy.org>


   I've read a paper or two on this and the idea has merit.  Open to
   question is whether one has a stem cell gone bad or whether one has a
   cancer cell activating stem cell genes.  As an interesting aside, I
   just looked at the genes in the cancer genome anatomy project and it
   looks like they are tracking 1519 genes (these are the genes found to
   be mutated in vivo in cancers).  Of course the common culprits, KRAS,
   BRAF, HRAS, EGFR, APC, KIT, RB, FGFR, are among the top 20 in terms of
   number of different mutations (presumably they have more locations
   which can be disrupted and result in uncontrolled growth).  Though the
   recent Nature on work by the project (Greenman et al 2007) felt that
   there were 120 kinase genes that served as "drivers" for the
   development of cancers [1].
   The problem with the stem cell theory, in spite of what the cited
   article says, is that it doesn't provide you with many new therapy
   options.  Many chemotherapeutic agents are designed to disrupt stem
   cell division (which is why you have side effects like nausea (stomach
   and intestinal stem cell disruption), hair loss (hair stem cell
   disruption), decline in blood cell counts (bone marrow stem cell
   disruption), etc.  If anything it suggests that one will need more
   intense, or longer, chemotherapies to kill off all of the stem cells.
   The only way out of this is going to be more complex targeted
   chemotherapies designed to seek out and kill specific types of stem
   cells (some of which people are labeling as "nanomedicine" --
   presumably to attract funding).  Those are coming but they are going
   to take some time and they aren't going to be cheap magic bullets.
   Robert
   1. Though the numbers are large, the good side of this is that we do
   have current technologies to design chips that would be able to
   rapidly survey this number of genes and determine precisely which are
   mutated.  This in turn allows one to develop targeted therapies.  But
   there are very few physicians currently equipped to do these types of
   tests and use the resulting information productively.

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Eugen* Leitl <a href="http://leitl.org">leitl</a> http://leitl.org
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