Fig. 2. Application of iPSCs to regenerative medicine.

In theory, any somatic cell type can be reprogrammed into an iPSC, but in practice, easily accessible cells, such as those from skin, urine or blood, are commonly used. Upon the acquisition of iPSC clones by transfecting reprogramming factors into the cells, a single clone is selected and expanded indefinitely and homogeneously. As new technologies have simplified the genome editing of iPSCs, iPSCs can be genetically modified precisely at the clonal level (green cells). The expanded cells can be used to establish a master cell bank or differentiated to specific cell types of interest for various purposes including cell therapies.