PTEN and cancer: The bioengineering of MSCs to express other tumour suppressor proteins, such as bone morphogenetic protein 4 (BMP4), or phosphatidylinositol 3,4,5-trisphosphate 3-phosphatase (PTEN), has also explored and further demonstrated the versatility of MSCs in cancer therapy, opening new ways for the development of more effective and targeted cancer treatments [144,145,146].