As mentioned in the article, transplanted MSCs have not been found to carry risk of tumor formation, and this is seen as one of their advantages.

Induced stem cells (IPS), or stem cells that are genetically modified may carry these risks, as there is overlap in the signaling mechanisms that maintain the undifferentiated state of stem cells, and that of tumor. In fact, stem cells naturally express more tumor-suppressing proteins as they age, which is thought to be a mechanism to prevent tumorigenesis resulting from damage accrued in the cells over time.