Human leucocyte antigen-G 14-bp InDel polymorphism and oral squamous cell carcinoma risk in Chinese Han population: A case-control study.

Abstract

Human leucocyte antigen-G (HLA-G) is a nonclassical HLA class I molecule involved in tumour immune escape. The purpose of this study was to investigate the association between the 14-bp insertion/deletion (InDel) polymorphism in the 3' untranslated region (3'-UTR) of HLA-G gene and oral squamous cell carcinoma (OSCC) risk in Chinese Han population (216 cases and 193 healthy controls), and furthermore, to evaluate serum soluble HLA-G (sHLA-G) levels in the OSCC patients. Our results demonstrated that the Ins allele was significantly less frequent in the OSCC patients than that in the healthy controls (odds ratio [OR]=0.75; 95% confidence interval [CI]: 0.57-0.99; p=0.040). Distribution of the 14-bp genotypes in the OSCC patients and the healthy controls revealed that the Ins/Ins genotype was associated with decreased OSCC risk in both the codominant model (Ins/Ins versus Del/Del; OR=0.57; 95% CI=0.33-0.99; p=0.044) and the log-additive model (OR=0.76; 95% CI: 0.58-0.99; p=0.044). The serum sHLA-G level was significantly higher in the OSCC patients than those in the healthy controls (p<0.001). Receiver operating characteristic (ROC) curve revealed the valuable diagnostic value of sHLA-G for OSCC detection, with an area under the ROC curve (AUC) of 0.891 (95% CI: 0.856-0.925, p<0.001). The OSCC patients with Ins/Ins genotype had lower serum sHLA-G levels than those with Ins/Del and Del/Del genotypes (p=0.015). Furthermore, serum sHLA-G levels were significantly increased with the increasing TNM stages of the OSCC patients (p=0.017). Our findings revealed that the HLA-G 14-bp InDel polymorphism might be a genetic risk factor for OSCC susceptibility, and the serum sHLA-G may act as a promising biomarker for noninvasive diagnosis of OSCC.