Table 1.

Properties and differences between ES, iPS and AFS cells.

Properties	ES	iPS	AFS
Naturally existing stem cells	Yes	No	Yes
Self renewal capacity	Yes	Yes	Yes
High proliferation efficiency	Yes	Yes	Yes
Pluripotent marker expression	Yes	Yes	Yes
Differentiation in three germ layers	Yes	Yes	Yes
Risk for teratoma formation	Yes	Yes	No
Ectopic oncogene expression	No	Yes	No
Immunological compatibility with recipient	Yes/No	Yes/No	Yes/No
Possessing prenatally lethal mutations	Yes	No	Yes/No
Disease-specific stem cells	Yes	Yes	Yes
Disease specific stem cells with known patient’s phenotype	No	Yes	Yes
Risk for chromosomal aberrations from the donor cells	No	Yes/No	No
Risk for aberrations acquired during reprogramming	No	Yes	No
Epigenetic deregulation	No	Yes	No
Studies on drug testing	Yes	Yes	Yes
Legal restrictions	Yes	No	No
Ethical concerns	Yes	No	No