Genetic instability of modified stem cells - a first step towards malignant transformation?

Induced pluripotent stem cells (iPSC) are important tools in regenerative medicine. Yet, it is becoming increasingly clear that the reprogramming process, including retroviral transduction with potent oncogenes like c-Myc and long-term cultivation, may induce genetic instability. Genetically altered iPS cells can grow out and dominate the cell culture. This review intends to comprehensively summarize the current knowledge on genetic instability of embryonic and iPSCs, with an emphasis on cytogenetic alterations, and compares these data with what is known from tumorigenesis.