Table 1.

Characterization of surface markers of CSC in the tumor immune microenvironment

CSCs	Phenotypes of CSCs	Immune cell Involving CSCs	Immune mechanism of CSCs	Ref
EpCMA	Liver CSCs	NK cell;	The high expression of EpCAM + cells resulting in resistance to NK cell-mediated cytotoxicity	[26]
CD44	SCCHN CSCs	Treg cells; MDSC;	CD44 + cells inhibit T-cell proliferation, Treg cells and MDSC	[27]
CD44	Lung CSCs	B cell; CD4 + T cell; Neutrophil; DC;	CD44 was associated with PD-L1 and infiltration of immune cells, and was a negative prognostic factor for predicting worsed OS in lung adenocarcinoma	[28]
CD44 + /CD133 +	Pancreatic CSCs	CD8 + T Cell;	CD44 + /CD133 + CSCs are associated with low CD8 + T cell infiltration and high PD-L1 expression Level	[29]
CD44 + CD90 +	SCLC CSCs	CD8 + T Cell;	The interaction between CD44 + CD90 +  CSC-like cells and T cells led to the upregulation of checkpoint molecules PD-1, CTLA-4, TIM-3, and LAG3	[30]
CD90	Pancreatic CSCs	Monocyte; Macrophage;	The CD90 highly expressed population in PDAC cells harbors high stemness features and tumorigenicity. Notably, CD90 acts as an anchor for monocyte/macrophage adhesion, providing immunosuppressive features	[31]
CXCR4	OSCC CSCs	CAF; TAM; Monocytes;	CAF effectively attracts monocytes via the CXCL12/CXCR4 pathway and induces their differentiation to M2 macrophages	[32]
CD166	Lung CSCs	DC vaccine	Dendritic cell vaccination significantly decreased percentage of CD166 + CSC.This anticancer stemness effect was attributed to the immune-stimulatory effect as indicated by increased percentage of CD83 + and CD8 +  cells, upregulation of Il-12, and downregulation of TGF-β, CTLA-4, PD-L1 and FOXP3 gene expression compared to lung cancer control group	[33]
SOX2	Colorectal CSCs	CD8 + T cell; Treg cells;	The prognostic value of the SOX2 cancer stem-like cell marker in colon cancer is modified by expression of immune-cell related factors FoxP3 and PD-L1	[34]
Nanog	Colorectal CSCs	CD8 + T cell;	Inhibition of Nanog in a murine model of colon cancer rendered tumor cells susceptible to immune-mediated clearance and led to successful, long-term control of the disease	[35]

SCCHN Squamous cell carcinoma of the head and neck, SCLC Small cell lung cancer, OSCC Oral squamous cell carcinoma, NK Natural killer, Treg cells Regulatory T cells, MDSC Myeloid-derived suppressor cells (MDSC), DC Dendritic cell, CAF Cancer-associated fibroblast, TAM Tumor-associated macrophage