Expression of human leukocyte antigen G (HLA-G) correlates with poor prognosis in gastric carcinoma

Objective: We had previously demonstrated that human leukocyte antigen G (HLA-G) was expressed in a majority of primary colorectal carcinomas and that the detection of HLA-G expression had a strong and independent prognostic value for that cancer. Currently, we investigate whether or not HLA-G is also expressed in patients with gastric carcinoma and whether the expression has any clinical application value. Methods: The expression of HLA-G was investigated immunohistochemically in 160 patients with gastric carcinoma. The correlation between HLA-G status and various clinicopathological parameters was analyzed with the levels of HLA-G expression used to compare the survival length amongst patients. Results: HLA-G protein expression was observed in 71% (113 of 160) of the primary site of gastric carcinomas, but not in the normal stomach tissues. HLA-G expression in the tumors was significantly correlated with the tumor location, histological grade, depth of invasion, lymph nodal metastasis, clinical stages of the disease, and host immune response (P = .012, .008, .001, .038, .030, and .016, respectively). Patients with HLA-G positive tumors had a significantly shorter survival time than those patients with tumors that were HLA-G negative (P = .001). As well, in multivariate analysis, HLA-G demonstrated an independent prognostic factor (P = .0001, relative risk 9.08; 95% confidence interval, 3.44-24.0). Conclusions: Overall, our results indicated that the expression of HLA-G is a characteristic feature of gastric carcinoma and that immunostaining by anti-HLA-G antibody may be a potentially useful prognostic indicator.