Plasma soluble human leukocyte antigen G predicts the long-term prognosis in patients with colorectal cancer.

Background: Colorectal cancer (CRC) is the third most common tumor in the world. It is crucial to further screen for indicators that are strictly related to long-term prognosis. Human leukocyte antigen G (HLA-G) is closely involved in tumor development. This study aims to evaluate the long-term predictive value of soluble HLA-G (sHLA-G) in CRC through a double-center retrospective study.

Methods: Patients who underwent radical CRC surgery in two hospitals from April 2010 to March 2015 were included. Baseline data of the patients were collected. The patients' preoperative baseline plasma sHLA-G level was detected. According to whether they survived during five years of follow-up, these patients were divided into two groups. Univariate and multivariate analysis were used to find factors associated with survival. The receiver operation curve (ROC) was performed to analyze the relationship between sHLA-G level and five-year survival, and the cutoff value was obtained. The baseline data and follow-up results of the two groups of patients were compared, and the Kaplan-Meier survival curve was used to analyze the difference in the long-term prognosis of the two groups of patients.

Results: A total of 1,037 cases were included and followed up for more than five years. Three hundred two cases (29.1%) died during the five-year follow-up. The baseline data of the survival group and the death group showed that the baseline level of sHLA-G in the survival group was significantly lower than the death group (41.4±16.9 64.7±23.2, P<0.05). Univariate and multivariate analyses suggest that age, differentiation, family history, TNM stage, and baseline sHLA-G levels are important factors affecting the survival of CRC patients. The area under ROC of sHLA-G with five-year survival is 0.766, and the cutoff value is 50.8 U/mL. The specificity at this point is 78.1%, and the sensitivity is 72.3%. The Kaplan-Meier survival curve showed that the five-year prognosis of patients in the low-level group was better than that in the high-level group.

Conclusions: Lower baseline sHLA-G level predicts better prognosis during a five-year follow-up in colorectal cancer patients.