Table 5.

External (microenvironmental) modulators of stemness.

Factor	Cell line (cancer)	Effect on stemness	Reference
Extracellular ATP	Gliomas	↓	[69]
High energy metabolites (lactate and ketones)	MCF-7 (breast)	↑	[70]
Hypoxia and the hypoxic microenvironment	Prostate, brain, kidney, cervix, lung, colon, liver, and breast tumors	↑	[71–74]
Hepatocyte growth factor	Colon	↑	[75]
VEGF	Skin	↑	[76]
VEGF	Gliomas	↑	[77]
Nitric oxide	Gliomas	↑	[78]
Retinoic acid	Gliomas	↓	[79]
ROS	Breast	↑	[80]
Conditioned medium	DU145	↑ or ↓ depending on the media	[81]
	Non-cancer
Hypoxia	Embryonic stem cells	↑	[82]
Hypoxia	Human embryonic stem (hES) cells	↑	[83]