A team at the governmental scientific research institute Riken on Sept. 12 transplanted a retina sheet made of induced pluripotent stem (iPS) cells into a woman — the world's first clinical research involving the transplant of human iPS cells. The surgery represents an important step that may lead to the application of iPS cells in the treatment of disease. Since iPS cells are touted as a powerful tool in the field of regenerative medicine, the world will pay attention to the results of the Riken team's transplant.

Still, it must not be forgotten that the main purpose of this clinical research should be to confirm the safety of the transplant. Instead of trying to quickly obtain conclusions from the transplant, researchers and other parties concerned should calmly evaluate the clinical test results in a multi-faceted manner. This process will be indispensable in making regenerative medicine reliable and effective.

In 2007, Kyoto University professor Shinya Yamanaka developed iPS cells that could grow into any type of tissue in the human body by adding four genes to mature skin cells. Because iPS cells have applications in regenerative medicine and in the development of new drugs, his research won him the 2012 Nobel Prize in Physiology or Medicine, which he shared with fellow researcher John Gurdon.