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The Body Electric
disease: The simpler the cells, the faster they grow and the harder they
are to treat, whereas a tumor that still resembles its tissue of origin is
less malignant.
The second criterion is growth rate. Cancer cells multiply wildly, in
contrast to the slow, carefully controlled mitosis of normal cells. Going
hand in hand with this uncontrolled proliferation is a similar lack of
control in the structural arrangement of the cells. Their membranes
don't line up in the normal, specific ways, and they form a jumbled
mass instead of useful architecture. As a further result of runaway multi-
plication, cancer doesn't observe the "boundary laws" of normal tissue.
Instead it encroaches imperialistically upon its neighbors. In addition,
since the cells don't adhere in any kind of structure, some of them are
constantly breaking off, flowing through the blood and lymph, and set-
ting up colonies—metastases—throughout the body.
The third basic criterion of cancer is metabolic priority. The diseased
tissue greedily takes first choice of all nutrients circulating in the blood;
the healthy part of the body gets what's left over. As the tumors dis-
seminate and grow, they consume all available food, and the host wastes
away and dies.
We can make one crucial observation at this point: Except for the lack
of control, all three characteristics—cell simplicity, mitotic speed, and
metabolic priority—are hallmarks of two normal conditions, embryonic
growth and regeneration.
When considering the similarities between an embryo and a tumor,
it's important to keep in mind one difference. Even though contained
within the body of its mother, the embryo is a complete organism, and
the controls over its cells are primarily its own, not those of an adult.
Over thirty years ago in Switzerland, G. Andres probed this relationship
by implanting frog embryos in various body tissues of adult frogs.
Whenever the host didn't simply reject the graft, the embryo degener-
ated into a highly malignant metastasizing tumor. As a result, Andres
proposed a theory of cancer that remains provocative today: A normal
cell becomes cancerous by dedifferentiation. This change is not dan-
gerous per se, according to Andres, but, because it occurs in a postfetal
animal, the controls that would normally hold these neo-embryonic cells
in check aren't working.
Cancer's relationship to regeneration is even more interesting. In the
latter, a rapid growth of primitive cells having metabolic priority occurs
in an adult, but with proper control as in an embryo
Those animals that
regenerate best are least susceptible to cancer. In general, as complexity
increases up the evolutionary ladder to humans, regenera-