Diagnostic significance of soluble human leukocyte antigen-G for gastric cancer.

Human leukocyte antigen-G (HLA-G) is a novel tumor marker. Increased level of soluble HLA-G (sHLA-G) in various tumor types has been reported. However, the potential diagnostic value of sHLA-G with other tumor markers in gastric cancer (GC) diagnosis is yet to be explored. In this study, plasma level of sHLA-G was measured in 81 GC patients, 53 benign gastric disease patients and 77 normal controls by ELISA. The serum levels of alpha fetoprotein (AFP), carcinoembryonic antigen (CEA), cancer antigen 125 (CA125), cancer antigen 19-9 (CA19-9) and cancer antigen 72-4 (CA72-4) were also determined. Data showed that plasma level of sHLA-G in GC was dramatically increased compared with normal controls and benign gastric disease patients (both p<0.001). The AUC for sHLA-G was 0.730 (p<0.001), superior to serum AFP, CEA, CA125, CA19-9 and CA72-4. After evaluating three cut-offs of sHLA-G, we concluded sHLA-G (cut-off at 128U/ml) plus CA125 in two-biomarker panel test and CA125 plus CA199 plus sHLA-G or CA125 plus CA724 plus sHLA-G in three-biomarker panel test were better choices for GC discrimination. Our findings indicated that sHLA-G was a potential biomarker for GC diagnosis and the combination of sHLA-G with CA125, CA19-9 and CA72-4 can improve the clinical screening and diagnosis for GC.