|THE LIVING CELL|
A look at the world of the cell
with Boyce Rensberger
May 16, 1997
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in this forum:
Are cancer cells "anarchists" in the body "republic?" Will human organs ever be genetically engineered? What makes humans different from chimpanzees? Will cloning lead to the lose of human individuality? Why hasn't the abortion debate included new information on how human life develops? Where will the most exciting advances in biology come from in the next century?
David Gergen discusses the cellular world with Boyce Rensberger, author of "Life Itself: Exploring The Realm of the Living Cell."
April 24, 1997:
Charlayne Hunter-Gault talks with the doctor who helped a 63-year-old woman become a mother.
March 5, 1997:
The annoucement of Dolly, the cloned sheep, was stunning, but what does cloning mean for society?
February 24, 1997:
Analysis of the revelation that Scottish scientists had cloned a sheep.
January 1, 1997:
Paul Solman reviews the year in genetics.
Browse the NewsHour's index of science coverage.
William Mueller of Sacramento, CA, asks:
The description of the cells in our bodies as a "republic" is fascinating. My question is: are cancer cells simply unrepentant "anarchists" or are they "super patriots" striving to form a rival republic, damn the consequences?
Boyce Rensberger responds:
Well, it is possible to push a metaphor too far.
All cancers start out as a single cell that had been a loyal citizen of the republic. But once that single cell accumulates enough mutations in the right genes (it usually takes several to turn a citizen into an anarchist), the cell revolts. Instead of converting other citizens to the cause, however, the only way the original renegade can enlarge its movement is by reproducing. The rebellious cell divides and its progeny keep dividing, each inheriting the mutated genes. Thus far, I would say the cancer cells are unrepentant anarchists.
But then, some additional things happen that make the tumor more like the rival republic you suggest. Once a tumor grows beyond a certain size, it needs its own blood supply. So tumor cells send out chemical substances that signal blood vessels to grow into them. They are called angiogenesis factors, and as long as the tumor secretes them, blood vessels (made of normal, nontumor cells) snake into the tumor, sprouting branches and capillaries to bring food and oxygen to what you might now call a rival republic.
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