Serum sHLA‐G levels: A useful indicator in distinguishing colorectal cancer from benign colorectal diseases

Soluble human leukocyte antigen‐G (sHLA‐G) has been reported in malignancies and is implicated in mediating immune surveillance of tumor. The aim of our study is to detect serum sHLA‐G levels in colorectal cancer and to determine whether sHLA‐G may be helpful in distinguishing colorectal cancer from benign colorectal diseases. Serum sHLA‐G levels were determined using enzyme‐linked immunosorbent assay. Receiver operating characteristic (ROC) curve was used to evaluate the feasibility of sHLA‐G in differentiating colorectal cancer from benign colorectal diseases. Median sHLA‐G concentrations were significantly higher in colorectal cancer compared to normal colorectum, hyperplastic polyp, inflammatory bowel disease and adenoma (all at p < 0.001, respectively). ROC curve for sHLA‐G revealed an area under the curve of 84.2%, and when 88.6 U/mL was used as cutoff, a sensitivity of 72.2% and a specificity of 87.8% were achieved. Comparison of sHLA‐G and carcinoembryogenic antigen ROC curves indicated that sHLA‐G was superior to CEA in differentiating colorectal cancer from benign colorectal diseases (p < 0.001). ROC curves analysis of the combined sHLA‐G and CEA showed a higher detection capacity (area under the ROC curve, 87.4%) than that of markers considered singly. These findings reveal that serum levels of sHLA‐G are significantly increased in colorectal cancer which may serve as a potent mediator of immune escape in colorectal cancer, and sHLA‐G may be a useful indicator in differentiating colorectal cancer from benign colorectal diseases.