Amniotic epithelial cells (AECs) possess unique characteristics, which make them a suitable source for cell-based therapeutic strategies. AECs have stem cell properties with low-immunogenicity (due to expressing HLA-G molecule and absence of MHC class I and II antigens) and no ethical problems, as well as availability in sufficient numbers, which can be obtained from a placenta. We have recently shown that the AECs have anti-cancer properties due to inhibition of angiogenesis, induction of apoptosis and cell cycle arrest probably through inhibition of HSP90. Since the viability of AECs must be improved after in vivo administration in acidic microenvironment of tumor, we clarify here that low pH preconditioning of AECs would lead to more survival of implanted cells in tumor site as well as improved functional outcomes.