胃癌（GC）是全球第五常见的恶性肿瘤，与晚期诊断相关的死亡率较高。虽然GC诊断的金标准是内窥镜活检，然而，这种方法不具备成本效益，且对患者具有侵入性。人类白细胞抗原G（HLA-G）分子是免疫应答的一个检查点。在癌症中的过表达与免疫逃避、转移、预后不良和总体生存率降低相关。我们使用ELISA试验评估了GC和良性胃病患者的可溶性HLA-G（sHLA-G）的血浆水平。我们的主要发现是，GC患者的sHLA-G浓度高于良性病变患者，与男性相比，女性GC患者的血浆sHLA-G水平较高，并且良性胃病受评估的sHLA-G水平之间存在显著差异。在我们的研究人群中，GC评估的阶段没有发现显著差异，我们认为sHLA-G不是一个适合用于GC分期的标记物，但它具有诊断潜力。除了提供sHLA-G作为GC诊断标记物的潜力信息外，我们的研究还证明HLA-G分子可以存在于外泌体的细胞膜中，这凸显了需要进行更多样本的研究以探索HLA-G阳性外泌体在胃癌情境中的功能影响，并确定这些发现在非侵入性诊断方法开发中的临床意义和可能应用。© 2023.Springer Nature Limited.

Gastric cancer (GC) is the fifth most frequent malignancy worldwide and has a high mortality rate related to late diagnosis. Although the gold standard for the GC diagnosis is endoscopy with biopsy, nonetheless, it is not cost-effective and is invasive for the patient. The Human leukocyte antigen G (HLA-G) molecule is a checkpoint of the immune response. Its overexpression in cancer is associated with immune evasion, metastasis, poor prognosis, and lower overall survival. We evaluate the plasma levels of soluble HLA-G, (sHLA-G) in patients with GC and benign gastric pathologies using an ELISA test. A higher concentration of sHLA-G in patients with GC than in those with benign pathologies, higher levels of plasma sHLA-G in women with GC compared with men and significant differences in the sHLA-G levels between the benign gastric pathologies evaluated, was our main findings. As no significant differences were found between the GC assessed stages in our study population, we suggest that sHLA-G is not an adequate marker for staging GC, but it does have diagnostic potential. In addition to providing information on the potential of sHLA-G as a diagnostic marker for GC, our study demonstrate that HLA-G molecules can be found in the membrane of exosomes, which highlights the need to perform studies with a larger number of samples to explore the functional implications of HLA-G positive exosomes in the context of gastric cancer, and to determine the clinical significance and possible applications of these findings in the development of non-invasive diagnostic methods.© 2023. Springer Nature Limited.