Inhibition of host immune response in colorectal cancer: Human leukocyte antigen-G and beyond

Table 2 Summary of human leukocyte antigen-G evaluations in colorectal cancer and related colonic diseases of the gastrointestinal tract

Sample type	HLA-Gs	Methods	Disease, n	Relevances	Ref.
Tumor DNA	HLA-G	RT-PCR	CRC, n = 39	HLA-G mRNA was significantly more expressed in CRC (87.2%) than in the extra neoplastic tissue	[24]
Tumor tissue	HLA-G	IHC	CRC, n = 201	HLA-G is over-expressed in primary CRC sites (64.6%), but not in the normal CRC tissues or benign adenomas	[25]
Tumor tissue	HLA-G	IHC	UC, n = 24; CD, n = 19	HLA-G and IL-10 are highly expressed in UC but not in CD tissue biopsies	[154]
Tumor tissue	HLA-G	IHC	CRC, n = 60; DA, n = 67; BC, n = 37; AC, n = 52	HLA-G is over-expressed in 52 % of CRC lesions and also in 79% of PDAs, 76% in BC and 75% AC	[26]
Tumor tissue	HLA-G	IHC	CRC, n = 415	HLA-G is expressed in > 30% of CRC lesions (data summarize published data collected until 2008)	[16]
Tumor tissue	HLA-G	IHC	CRC, n = 154	HLA-G is expressed in > 30% of CRC lesions (data summarize published data collected until 2005)	[17]
Serum	sHLA-G	ELISA	CRC, n = 144	Higher sHLA-G levels in CRC (median 124.3 U/mL) compared to benign colorectal diseases (cut off value 88.6 U/mL). CEA showed less sensitivity e specificity	[27]
Plasma	sHLA-G	ELISA	CRC, n = 37	sHLA-G as a diagnostic biomarker for the detection of early CRC (median 84 U/mL) with respect to BD (median 34 U/mL)	[28]
PBMC	sHLA-G	ELISA	HD, n = 30; CD, n = 10; UC, n = 18	Spontaneous secretion of sHLA-G from cultured PBMCs of CD but not in UC and BD	[161]
				Secretion of sHLA-G in CD patient cultures and BD but no in UC, after LPS stimulation
Plasma and PBMC	HLA-G	ELISA	UC, n = 27; CD, n = 22	Immunosuppressive therapy decreases sHLA-G hyperproduction in CD and induces its release in UD, in both plasma and in PBMC culture supernatants	[162]

HLA-G: Human leukocyte antigen-G; sHLA-G: Soluble HLA-G; CRC: Colorectal cancer; UC: Ulcerative colitis; CD: Crohn’s disease; PDA: Pancreatic ductal adenocarcinoma; BC: Biliary cancer; AC: Ampullary cancer; HD: Healthy blood donors; PBMC: Peripheral blood mononuclear cells; IHC: Immunohistochemistry; LPS: Lipopolysaccharide; CEA: Carcinoembryonic antigen; IL: Interleukin; ELISA: Enzyme-linked immunosorbent assay.