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0:05
One major concept
I would like to
discuss is this multi-step
metastasis model.
In there the EMT program
is actually not a
one-way street.
The reason I say that
is because we all know
that when the patient
developed distant metastasis,
the distant metastasis
actually present
many of the same features
of the primary tumor.
What I mean is, if you
have a breast cancer,
the distant metastasis also is
a breast tumor and
may still express ER,
or still express HER2 and still
maintain a relative
epithilioid morphology.
There are a lot of
debate in the field.
If the distant
metastasis do not look
like a sarcoma does not look
like a mesenchymal tumor,
how can EMT program play a role?
I think that brought up to
this very important concept that
EMT is not a one-way street.
Tumor cells actually
appear on this program to
allow the invasion and
intravasation, the extravasation.
By that distant site,
we think this program
probably needs to be
turned off to allow
this migrated cell to
actually now stay in
a distant site to
start to regrow and
colonize the distance site.
In the next few slides,
I would like to show you
some of the evidence from
animal models to show the
importance of this plasticity.
1:30
But before I go on,
I want to show you the
evidence why we think
EMT plasticity exists
in human cancer.
I think the best
place to look at
this plasticity in human patient
is in circulating tumor cells.
This is the early
study from Ming Hu,
the isolated
circulating tumor cells
from breast cancer patients.
You can see there's 17
patients than they stained for
either epithelial or
mesenchymal markers defined
the circulating cell
either they're E
or EM or M.
As you can see here in the
majority of the patient,
there are highly
enriched sub population
of the cell that present
a mesenchymal signature.
And this has been reported
not only in breast cancer,
but also in many type of
human eye carcinomas.
So what this suggests is
that the enrichment of this
more mesenchymal
phenotype, this is a much
higher than present
in a primary tumor.
Usually the more
mesenchymal cell cannot be,
go over 10 percent.
Is that turning on this
program probably gave
this tumor cell the
advantage to be able to
enter the circulation
to become CTC.