Published online Apr 14, 2014. doi: 10.3748/wjg.v20.i14.3778
Revised: January 22, 2014
Accepted: February 26, 2014
Published online: April 14, 2014
Processing time: 170 Days and 14.4 Hours
Colorectal cancer (CRC) is one of the most diffuse cancers worldwide and is still a clinical burden. Increasing evidences associate CRC clinical outcome to immune contexture represented by adaptive immune cells. Their type, density and location are summarized in the Immune Score that has been shown to improve prognostic prediction of CRC patients. The non-classical MHC class I human leukocyte antigen-G (HLA-G), is a crucial tumor-driven immune escape molecule involved in immune tolerance. HLA-G and soluble counterparts are able to exert inhibitory functions by direct interactions with inhibitory receptors present on both innate cells such as natural killer cells, and adaptive immune cells as cytotoxic T and B lymphocytes. HLA-G may play a prominent role in CRC strategies to avoid host immunosurveillance. This review highlights the current knowledge on HLA-G contribution in CRC, in related inflammatory diseases and in other type of cancers and disorders. HLA-G genetic setting (specific haplotypes, genotypes and alleles frequencies) and association with circulating/soluble profiles was highlighted. HLA G prognostic and predictive value in CRC was investigated in order to define a novel prognostic immune biomarker in CRC.
Core tip: Colorectal cancer (CRC) prognosis is strictly associated with the immune contexture of tumor microenvironment. IS improves prognostic prediction in CRC. Human leukocyte antigen-G (HLA-G) through its direct inhibitory functions on NK cells and cytotoxic T and B lymphocytes represents a crucial tumor-driven immune escape molecule. This review highlights the current knowledge on HLA-G in CRC and in related inflammatory diseases. HLA-G genetic setting and circulating/soluble profiles need to be defined to comprehend CRC strategies to avoid host immune defences. We suggest that HLA G could represent a novel prognostic immune biomarker to associate with the Immune Score to better characterize host immune response in CRC.