In November Japanese researchers showed that adult human and mouse skin cells could be reprogrammed into stem cells similar to embryonic stem cells, which can be transformed into any type of cell. These cells, called induced pluripotent stem cells (iPS), has the potential to be a major step forward in using stem cells to cure a variety of diseases. A major concern with using such stem cells (iPS) to treat disease has been the possibility that the retrovirus used to implant the cells might cause cancer, but now a group of Japanese scientists solved that problem.

In a study, published in the Feb. 14 issue of Science, the Japanese researchers prove these stem cells are made from normal mature adult cells, and they show that these stem cells can be implanted using a retrovirus without fear of causing cancer.

“It will still take years of basic research before we become able to use iPS cells to treat patients,” said lead researcher Dr. Shinya Yamanaka, from Kyoto University in Japan. “We are doing our best to bring it to clinics as quick as possible.” I am really happy that Japanese researchers are taking a lead on this as US has traditionally been encumbered with so-called ethicists who opposed tooth and nail any progress in stem cell research.

In experiments with mice, Yamanaka’s team reprogrammed adult mouse liver and stomach lining cells into iPS cells. Using a retrovirus, the scientists were able to transplant these cells into mice. Moreover, Yamanaka’s team found that these reprogrammed cells avoided sites that are known to trigger tumors. In fact, mice that received the iPS remained tumor-free for six months.

The billion dollar question today is whether iPS cells will act like real embryonic stem cells in real life is yet to be determined.