Table 1.

Properties of mouse and human pluripotent cell populations grown in vitro (modif. according to Pera and Tam 2010 and Durcova-Hills et al. 2008)

Types of stem cells	Stem cell-associated genes								Cell surface markers			Response to factors			Developmental potential
	Oct4	Nanog	Sox2	Klf4	Dppa3	Rex1	Gbx2	Fgf5	SSEA1	SSEA3 SSEA4	Alkaline phosphatase	LIF	Nodal and/or activin	FGF2	Teratoma formation	Chimaera formation
Mouse EC cells	+	+?	?	?	?	+?	?	?	+	–	+	–?	–?	–	+	– (only somatic)
Mouse ES cells	+	+	+	+	+	+	+	–	+	–	+	+	–#	–	+	+
Mouse EG cells	+	+	+	+	+	+	?	–?	+	–	+	+	–?	+	+	+
Mouse EPL cells	+	+	+	ND	–	–	–	+	+	–	+	+§	ND	ND	+	–
Mouse EpiSCs	+	+	+	–	–	–	–	+	+	–	–	–	+	+&	+	–
Human EC cells	+	+	+	?	?	+	?	?	–	+	+	–	?			ND!
Human ES cells	+	+	+	+	+	+	+	–	–	+	+	–	+	+	+	ND!

+, The gene or cell surface marker is expressed, the growth factors are required for self-renewal or the cells form teratomas or chimaeras; –, the gene or cell surface marker is not expressed, the indicated factors are not required for self-renewal, or the cells do not form tumours or chimaeras, ND, not done; ND!, cannot to be done for obvious ethical reasons!

^#One study shows long-term self-renewal; ^§ EPL cells grown in LIF revert to an ES-like state; ^& EpiSCs are derived and maintained in the presence of these factors, but dependence on the factors for self-renewal has not been rigorously examined