Maybe it has also intrigued others why nobody hears about cancer of the
heart, yet we hear about cancer afflicting most other parts of the body.
If so, the article on the following Scientific American web page will be of
interest to you:
<http://www.sciam.com/askexpert/medicine/medicine51/>
The main thrust of this article is that "the heart........doesn’t get exposed
to many carcinogens, just those in the blood. That, combined with the fact
that the heart cells do not often replicate, is why you don’t see much cancer
of the heart muscle. Indeed, according to cancer statistics, it does not
appear to occur at any measurable rate. "
However, the cells of the human brain have long been identified as ones which
do not multiply very readily; in addition, the brain, like the heart is also
not directly exposed to carcinogens, except via its blood supply. Yet,
cancer of the brain and spinal cord is relatively common. Something in the
above explanation still does not ring quite true.
We do have to note that the heart does undergo exercise and pathological
('enlarged heart') hypertrophy. We know that training increases the volume
and cross-sectional area of muscles and that research is beginning to suggest
that certain types of very intensive training may also produce hyperplasia
(growth in cell number).
If the heart does not develop cancer, is the author of the article suggesting
that it is hyperplasia rather than hypertrophy which acts as a factor in the
causation of cancer? If so, then the fact that muscle cancer does occur may
offer further proof for the occurrence of hyperplasia. Either that, or
cancer must also affects cells which enlarge in size, but do not proliferate
in number.
Some interesting speculations are always possible when one reads articles
such as this one.
Dr Mel C Siff
Denver, USA
http://www.egroups.com/group/supertraining
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