Human leukocyte antigen-G in cancer: Are they clinically relevant?

The immunotolerant human leukocyte antigen (HLA)-G has direct inhibitory effects on natural killer cells (NK), dendritic cells (DC), T cells and can induce tolerant regulatory cells. The expression of HLA-G has been correlated with the tolerance of the fetus, the acceptance of organ transplants, and the immune escape of tumor cells and virus-infected cells. In the context of malignancies, aberrant induction of HLA-G expression has been extensively investigated and its clinical relevance has been postulated. We here focus on the HLA-G expression in malignancies and its relevance to tumor cell immune escaping and disease progression.

► HLA-G is an immunotolerant.
► Tumor cell restricted HLA-G expression was observed in various malignancies.
► Tumor cell or lesion HLA-G expression was associated with disease poor prognosis.
► Soluble HLA-G expression could be a potential diagnosis biomarker for malignancies.