Table 2.

Immunomodulatory molecules detected in CSCs/CICs

Molecule	Functiona	Activity in CSCs/CICsb	Reference
IL-4	Cytokine involved in differentiation of naïve T cells to Th2.	Inhibition of TH1 cell mediated immune responses.	[65, 118]
IL-10, IL-13	Anti-inflammatory cytokines	Suppression of CTL functions; differentiation of Tregs and MDSCs	[89, 119]
TGFB	Growth factor with potent inhibitory function	Tregs differentiation, inhibition of TH1 responses	[89, 120]
STAT3	Transcription factor with a potential anti-inflammatory function	Maintenance and proliferation of CSCs/CICs; differentiation of MDSCs, iDCs, M2	[115, 121]
GDF15	Growth and differentiation factor related to cellular stress.	Inhibition of anti-tumor immune responses	[122]
Galectin-3	Protein with important role in cell-cell adhesion and interactions with the extracellular environment.	Inhibitor of T cell mediated immune responses	[89, 123]
IDO	Enzyme involved in tryptophan catabolism	Suppression of TH1 type immune responses and differentiation of Tregs.	[34, 51, 64, 65, 123]
CD200	A glycoprotein that regulates myeloid cell activity and inhibits macrophage lineages.	Immune suppression and regulation of anti-tumor activity.	[124, 125]
PD-L1	Ligand of PD-1 and Immune checkpoint molecule	Inhibition of CTL immune responses.	[64, 65, 126, 127]
B7-H3 and B7-H4	Immune checkpoint molecules	Immunomodulation of cellular immune responses	[34, 64, 65, 128, 129]

^a: function of the molecules listed in the Table

^b: Activity of these molecules when expressed by CSCs/CICs

iDC: suppressive dendritic cell; MDSC: Myeloid derived suppressive cells; M2: M2 phenotype of monocytes/macrophages; TH1: T helper type 1; TH2: T helper type 2