The Nobel Assembly at Karolinska Institutet in Stockholm on Monday announced that Dr. Shinya Yamanaka of Kyoto University will share the Nobel Prize in Physiology or Medicine 2012 with Dr. John B. Gurdon of Cambridge University. We heartily congratulate Dr. Yamanaka on winning the world’s most well-known prize. It is hoped that his achievement will eventually help people suffering from difficult-to-cure diseases or debilitating injuries to live normal lives. His winning of the Nobel Prize will also serve as an incentive for Japanese scientists in the fields of basic medicine and biology, and even encourage ordinary citizens to take a greater interest in science.
Dr. Gurdon and Dr. Yamanaka are cited for their discovery that mature, specialized cells can be reprogrammed to become immature cells capable of developing into all the cell types — each carrying out a specific task — that form the body. The discovery challenged the dogma that the specialization of a cell is irreversible and has forced the rewriting of textbooks. The two scientists showed the importance of questioning a prevailing dogma and of carrying out trials and errors with carefully thought-out hypothesis.
In 1962, Dr. Gurdon removed the cell nucleus from a frog’s egg and injected into the egg a nucleus from a mature cell of a tadpole’s intestine. The egg developed into a tadpole. He eventually succeeded in producing adult frogs by using the method, proving that the nucleus of a mature, specialized cell can be returned to an immature cell with pluripotent capability of developing into all types of tissues. His research led to the cloning of mammals.
Dr. Yamanaka and his team succeeded in 2006 in creating pluripotent stem cells — immature cells that can develop into all types of cells in the body — by introducing only four genes into mature cells from the skin of a mouse. In 2007, they succeed in creating similar induced pluripotent stem (iPS) cells by using cells from the skin of a human. Dr. Yamanaka’s nomination for the Nobel Prize only five years after his 2007 achievement shows what a strong impact his discovery had on the world of medicine and biology.
Human iPS cells can multiply and develop into various tissues and organs but because their creation does not involve the use of a fertilized egg, they are free from the ethical problems peculiar to embryonal stem cells. They do not cause a rejection reaction, either. Therefore expectations are high that human iPS cells will be used to grow customized tissue for transplant. But the possibility that such cells can become cancerous cannot be ruled out. Many other questions about human iPS cells remain unsolved. Various hurdles must be overcome before such cells can be utilized for regenerative medicine. A new ethical problem also must be solved because it is theoretically possible to create human eggs and sperms by using the human iPS cells technology.
To ensure the healthy progress of the technology, the Japanese government and society need to resolve problems related to support for basic research, ethical and patent issues, and cooperation between the academia and industry, as Dr. Yamanaka points out.
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