Role of genetics vs. environment in the causation of cancer?
rellim at tulane.edu
Thu Sep 21 09:30:41 EST 2000
A report in the July 13 New England Journal of Medicine that described a
study of 90,000 twins concluded that "genetics" accounted for a small
portion of cancers, with "environment" playing the major role. The NEJM
editors really goofed up on this one.
This is a very strange conclusion to reach since only ~30% of the human
genome (and only very recently) is publicly available on Genbank and other
databases. Furthermore, we only somewhat understand the function of ~5% of
the genes in a human. It is difficult for me to see how one can make the
claim that cancer is mainly "environmental" when we only "sort of" know what
~5% of the genome does.
The damage was done when the media picked up this story and began to
(mis)interpret it. The general interpretation of the average reader was that
exposure to environmental pollution and contaminants (the public's concept
of the term "environment") is the main reason that people get cancer. The
fact that natural food-borne carcinogens, free radicals and other reactive
agents from normal metabolism, endogenous DNA damage, and replication errors
account for the bulk of mutations/cancer completely escaped discussion.
There is a nice rebuttal to the press articles and the NEJM article by
National Public Radio Science Correspondent Richard Harris in the MediaWatch
section of the latest issue of Current Biology Mediawatch entitled
"Environ-mental lapses" (Current Biology 2000, 10:R650). Scientists who
teach or communicate with general audiences and students should use Mr.
Harris' article, the NEJM paper, and the newspaper articles as a good
example of the miscommunication and misinterpretation of science and cancer
Charles A. Miller, III, Ph.D.
Associate Professor of Environmental Health Sciences
Tulane University School of Public Health and Tropical Medicine
1430 Tulane Ave.
New Orleans, LA 70112
(504)585-6942 rellim at tulane.edu
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