Introduction:
The diagnosis
of cancer consumes a large
percentage of many
pathologists' time. The huge
variety of types of tumors
that occur in people
requires complex analysis to
plan correct treatment and
to determine a patient's
prognosis. Diagnostic
testing enables pathologists
to learn how large a primary
tumor has grown, how
extensively it has spread
and — most importantly —
exactly what type of cancer
it is.
When they
think of cancer, most people
assume that these various
tumor types, once they
occur, are inexorable in
their progression unless
they are successfully
stopped by treatment.
Pathologists often think the
same way, in large part
because the examples we see
most often are in those
patients in whom cancer has
progressed to a size
sufficient to be detected.
Occasional
inklings from earlier
laboratory studies, however,
and some rare patient
reports, suggest that cancer
sometimes spontaneously
disappears without
treatment. Because such
cases are extremely rare,
and essentially impossible
to study, many scientists
have dismissed the
phenomenon of "spontaneous
regression" of cancer as
either a mistaken diagnosis
or fiction. Yet, such cases
have actually been carefully
documented in the past, and
they certainly do happen.
Do these
reports suggest that cancer
cells really do not grow "in
a vacuum," but are affected
by control mechanisms that
already exist in the body?
Does cancer reach a
detectable size because
these controls have failed?
If so, could such controls
be identified, and enhanced
in patients to provide new
therapies? In fact, how do
cancer cells actually
“succeed” in patients? Do
they actively inhibit
protective processes that
ordinarily would prevent
cancer? Do cancers occur
continuously during our
lifetimes, yet are
eliminated by internal
mechanisms so that they are
never seen?
The answers
to such questions are the
stuff of speculation, but a
newly discovered mouse at
Wake Forest University has
shown that some of these
ideas may not be so
far-fetched.
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