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Stem Cells

By Robert Bazell, Chief science correspondent

In the news about stem cells out today, part of the great fascination for me rests with the idea that we are learning more and more about one of the great wonders of life. How does a fertilized egg – a single cell – become the complex organism that is a mouse, an octopus or – yes a human being. That's what this is all about. The quest for that answer led scientists to find embryonic stem cells – cells that can grow indefinitely in the laboratory and have the potential to become heart, liver brain, kidney or any part of the body. They had first been discovered in mice and then when they were found in humans in 1999, the great speculation about their potential to cure disease arose – as did the controversy because scientists obtain them from embryos.

The complex choreograph of cells that starts with the fertilized egg involves many signals telling cells when to start growing and when to stop. When those signals go awry in a child or an adult the result is the unrestrained growth called cancer. That is why among many things, studies of stem cells reveal a grat deal about cancer.

The current wave of studies began last year when Dr. Shinya Yamanaka of Kyoto University found that only four genes put into mouse skin cells created cells that behaved just like embryonic stem cells. Imagine only four genes can unwind the entire series of events starting with the fertilized egg and make a skin cell behave like an embryonic cell!

In today's work Yamanaka and Dr. James Thompson's group at the University of Wisconsin show that the same can be done with human skin cells You can read the actual research papers here (http://images.cell.com/images/Edimages/Cell/IEPs/3661.pdf) (http://www.sciencemag.org/cgi/content/abstract/1151526)

There will be lots of discussion whether these discoveries will end the need to use embryos to get embryonic stem cells. One reason they might not gets back to cancer. The genes that cause the adult cells to revert to the embryonic state have a great potential to make the cells cancerous.

But let those discussions and the research continue. We can stand back at marvel at all we are learning about that wondrous thing called life.