However, there are several obstacles associated with iPSC-based therapy that will need to be addressed before routine clinical applications can begin153. One concern is the risk of tumorigenicity from ESCs and iPSCs154. Because pluripotent cells are maintained in culture for prolonged periods of time, they can accumulate karyotypic abnormalities, copy number variants, and loss of heterozygosity155. Hence prior to clinical use, iPSC-derived products need to be carefully screened for the lack of potentially risky genetic alterations155 and rigorously tested to ensure their purity, quality, and sterility. Increased knowledge on the basic biology of pluripotency induction and maintenance will also help us to reduce the risk of mutation development and genetic instability associated with human iPSC derivation and maintenance.
