Japanese researchers are about to start a clinical trial in cancer patients to assess treatment based on induced pluripotent stem cells, also known as iPS cells. This research is being conducted by Haruhiko Koseki of Riken research institute and Professor Yoshitaka Okamoto of Chiba University.
The trial will involve three patients with head and neck cancer—a recurrent cancer that cannot be treated surgically. The team will collect a type of white blood cell called the Natural Killer T cell , which attacks cancer cells and activates other cells in the immune system. The harvested cells will be converted into iPS cells, which will once again develop into Natural Killer T cells. The new NKT cells thus obtained will be transplanted to the three patients in three injections. The first injection will contain 30 million NKT cells. The next two injections will be adjusted depending on the positive or negative effects of the first injection.
In a previous study at Chiba University, injection of the patient’s own NKT cells reduced the number of cancer cells detected in the body. “Blood contains only a small number of cells and it takes time to culture them. However, the iPS cell count can easily be increased, thus facilitating the production of large numbers of Natural Killer T cells.”
Unconverted iPS cells could turn malignant, but this should not pose a problem in this experiment. Since they are derived from other individuals, the cells should, in fact, be eliminated by the patient’s immune system, regardless of whether or not they are malignant.