1570 2 Bueno C, Garcia-Castro J, Montes R et al. Human embryonic stem cells: A potential system for modeling infant leukemia harboring MLL-AF4 fusion gen. Drug Dis Today: Dis Models 2008;4:53–59. 3 Menendez P, Bueno C, Wang L. Human embryonic stem cells: A jour- ney beyond cell replacement therapies. Cytotherapy 2006;8:530–541. 4 Menendez P, Bueno C, Wang L et al. Human embryonic stem cells: Potential tool for achieving immunotolerance? Stem Cell Rev 2005;1: 151–158. 5 Przyborski SA. Differentiation of human embryonic stem cells after trans- plantation in immune-deﬁcient mice. Stem Cells 2005;23:1242–1250. 6 Prokhorova TA, Harkness LM, Frandsen U et al. Teratoma formation by human embryonic stem cells is site-dependent and enhanced by the presence of matrigel. Stem Cells Dev 2009;18:47–54. 7 Muller FJ, Goldmann J, Loser P et al. A call to standardize teratoma assays used to deﬁne human pluripotent cell lines. Cell Stem Cell 2010;6:412–414. 8 Cooke MJ, Stojkovic M, Przyborski SA. Growth of teratomas derived from human pluripotent stem cells is inﬂuenced by the graft site. Stem Cells Dev 2006;15:254–259. 9 Bueno C, Montes R, de la Cueva T et al. Intra-bone marrow trans- plantation of human CD34(þ) cells into NOD/LtSz-scid IL-2rgamma (null) mice permits multilineage engraftment without previous irradia- tion.Cytotherapy 2010;12:45–49. 10 Shultz LD, Lyons BL, Burzenski LM et al. Human lymphoid and mye- loid cell development in NOD/LtSz-scid IL2R gamma mice Teratoma Development from iPSCs and hESCs engrafted with mobilized human hemopoietic stem cells. J Immunol 2005;174:6477–6489. 11 Catalina P, Bueno C, Montes R et al. Genetic stability of human embryonic stem cells: A ﬁrst-step toward the development of potential hESC-based systems for modeling childhood leukemia. Leuk Res 2009;33:980–990. 12 Cortes JL, Sanchez L, Catalina P et al. Whole-blastocyst culture followed by laser drilling technology enhances the efﬁciency of inner cell mass isolation and embryonic stem cell derivation from good- and poor-quality mouse embryos: New insights for deriva- tion of human embryonic stem cell lines. Stem Cells Dev 2008; 17:255–267. 13 Cortes JL, Sanchez L, Ligero G et al. Mesenchymal stem cells facili- tate the derivation of human embryonic stem cells from cryopreserved poor-quality embryos. Hum Reprod 2009;24:1844–1851. 14 Barroso-delJesus A,Romero-Lopez C, Lucena-Aguilar G et al. Embry- onic stem cell-speciﬁc miR302–367 cluster: Human gene structure and functional characterization of its core promoter. Mol Cell Biol 2008; 28:6609–6619. 15 Catalina P, Montes R, Ligero G et al. Human ESCs predisposition to karyotypic instability: Is a matter of culture adaptation or differential vulnerability among hESC lines due to inherent properties? Mol Can- cer 2008;7:76–84. 16 International Stem Cell Banking Initiative.Consensus guidance for banking and supply of human embryonic stem cell lines for research purposes. Stem Cell Rev 2009;5:301–314.