Abstract
The discovery of a simple protocol capable of generating pluripotent stem cells from terminally differentiated cells has been one of the most promising breakthroughs in recent biomedical research. Since their discovery, manuscripts characterizing properties of induced Pluripotent Stem (iPS) have flooded the literature. Among others, the analysis of the transcriptome and epigenome of iPS is now a recurrent theme that is helping to understand the molecular mechanisms behind reprogramming. Recent works have revealed that transcriptional and epigenetic reprogramming is often incomplete, which has raised some concerns on the nature of iPS. Inevitably, now the genome itself of iPS has been scrutinized; and the reports come with an unexpected twist: the presence of mutations in the genome of iPS.