Department of Clinical Laboratory, The Second Hospital, Cheeloo College of Medicine, Shandong University, Jinan, China.
Shandong Engineering & Technology Research Center for Tumor Marker Detection , Jinan, China.
Front Immunol. 2021 Nov 11;12:791535. doi: 10.3389/fimmu.2021.791535. eCollection 2021.
As a non-classic major histocompatibility complex (MHC) class I molecule, human leukocyte antigen G (HLA-G) is expressed in fetal-maternal interface and immunoprivileged site only in healthy condition, and in pathological conditions such as cancer, it can be expressed. It is now widely accepted that HLA-G is a key molecule in the process of immune escape of cancer cells, which is ubiquitously expressed in the tumor environment. This raises the possibility that it may play an adverse role in tumor immunity. The expression level of HLA-G has been demonstrated to be highly correlated with clinical parameters in many tumors, and its potential significance in the diagnosis and prognosis of cancer has been postulated. However, because HLA-G itself has up to seven different subtypes, and for some subtypes, detected antibodies are few or absent, it is hard to evaluate the actual expression of HLA-G in tumors. In the present work, we described (a) the structure and three main forms of HLA-G, (b) summarized the mechanism of HLA-G in the immune escape of tumor cells, (c) discussed the potential role of HLA-G as a tumor marker, and reviewed (d) the methods for detecting and quantifying HLA-G.
作为一种非经典的主要组织相容性复合体（MHC）I 类分子，人类白细胞抗原 G（HLA-G）仅在健康状态下于胎儿-母体界面和免疫特权部位表达，而在癌症等病理条件下则可以表达。现在人们广泛认为，HLA-G 是癌细胞免疫逃逸过程中的关键分子，在肿瘤微环境中广泛表达。这就提出了它可能在肿瘤免疫中发挥不利作用的可能性。HLA-G 的表达水平已在许多肿瘤中与临床参数高度相关，并且其在癌症的诊断和预后中的潜在意义已被推测出来。然而，由于 HLA-G 本身有多达七种不同的亚型，并且对于某些亚型，检测到的抗体很少或不存在，因此很难评估 HLA-G 在肿瘤中的实际表达情况。在本工作中，我们描述了（a）HLA-G 的结构和三种主要形式，（b）总结了 HLA-G 在肿瘤细胞免疫逃逸中的机制，（c）讨论了 HLA-G 作为肿瘤标志物的潜在作用，并回顾了（d）检测和定量 HLA-G 的方法。
