Up-regulation of HLA-G expression in cervical premalignant and malignant lesions

The human leukocyte antigen G (HLA‐G) molecule, a non‐classical major histocompatibility complex class I antigen, exhibits highly limited tissue distribution and gene variation. Recent studies indicate strong immunoinhibitory properties in tumor cells that may favor their escape from anti‐tumor immune responses. However, the role of HLA‐G in cervical premalignant and malignant lesions has not been defined clearly. In our study, HLA‐G expression was studied in cervical tissue from 119 patients with lesions and 22 normal cervical tissue specimens by immunohistochemistry. HLA‐G was expressed in 45% (54/119) of cervical lesion‐containing tissues while it was rarely detectable (0/22) in the control specimens (P = 0.000). ROC curve analysis showed that HLA‐G has an area under the curve (AUC) of 0.694. Furthermore, we investigated soluble HLA‐G expression in the plasma of 172 patients with cervical lesions and 20 healthy controls. Significant increases were also observed in soluble HLA‐G levels (median, 191.4 vs 45.18 U/ml, P < 0.001). The relative operating characteristic (ROC) curves for soluble HLA‐G (sHLA‐G), squamous cell carcinoma (SCC), and carbohydrate antigen 125 (CA125) show an AUC of 0.710, 0.634, and 0.588, respectively. At the cut‐off values of 108.20 U/ml for sHLA‐G, 1.5 ng/ml for SCC, and 35 U/ml for CA125, the sensitivity was 73.30%, 47.83%, and 44.83%, respectively. The detection of soluble HLA‐G in plasma may have significance in the early detection of cervical malignant lesions.