Human leukocyte antigen-G in gynaecological tumours

Gynaecological tumours that threaten the health of women, especially when advanced and recurrent, have remained mostly intractable to existing treatments. Therefore, new therapeutic targets are urgently needed. Human leukocyte antigen-G (HLA-G) is a nonclassical major histocompatibility complex class I molecule typically expressed in foetuses for protection against destruction by the maternal immune system. HLA-G is also expressed under pathological conditions, such as in solid tumours, and may participate in tumour development and serve as a novel immune checkpoint in cancer. Furthermore, it is expressed in most gynaecological tumours. Therefore, inhibiting HLA-G and its receptors to block the immune escape pathway could represent a new strategy in cancer immunotherapy. To the best of our knowledge, this review is the first to summarize recent research findings on HLA-G in gynaecological oncology. We highlight the fact that HLA-G is expressed in gynaecological tumour tissues, wherein it inactivates immune effectors involved in tumour progression. Further studies on HLA-G in gynaecological oncology are needed to incorporate HLA-G into the design and evaluation of immunotherapy for malignant gynaecological diseases.