| Factors influencing tumorigenicity |
HESCs |
HiPSCs |
| Origin |
Inner Cell M ass cells that have undergone very few
divisions |
Mature somatic cells that have undergone many cell divisions |
| Derivation |
A relatively minor selection pressure* |
A major selection pressure owing to forced drastic change of epigenetic landscape
May result in mutations and/or aberrations owing to reprogramming stress |
| Viral integration |
Not applicable |
Most of the methods use viral vectors for reprogramming |
| Oncogenes activation |
Not applicable |
Current methods induce and up-regulate oncogenes in the reprogramming process |
| Cellular adaptation |
Prolonged growth in culture often results in gains of chromosomes 12, 17, 20 and X |
Prolonged growth in culture often results in gains of chromosome 12 |
