Objective To investigate serum β2-MG, sCHE, and PSGL-1 expression in patients with esophageal cancer and their relationship to lung infection after mediastinoscopy. Methods A total of 118 patients with esophageal cancer were selected and divided into infected and uninfected groups according to whether they developed lung infection after surgery. An automatic microbiological identification system was used to detect the pathogenic bacteria of lung infection. ELISA was used to detect the levels of β2-MG, sCHE, and PSGL-1. Multivariate logistic regression was used to analyze the influencing factors of postoperative lung infection in patients with esophageal cancer. ROC curves were plotted to analyze the assessment value of serum β2-MG, sCHE, and PSGL-1 on postoperative lung infection. Results Fifty-two strains of bacteria were isolated from the sputum of 38 patients with postoperative lung infections, and these included 35 (67.31%) Gram-negative, 14 (26.92%) Gram-positive, and 3 (5.77%) fungal strains. The difference in long-term smoking history between the infected and uninfected groups was statistically significant (P<0.05). Serum β2-MG and PSGL-1 levels were significantly higher and sCHE levels were significantly lower in the infected group than in the uninfected group (P<0.05). Serum β2-MG and PSGL-1 levels were sequentially higher (P<0.05) and sCHE levels were sequentially lower (P<0.05) in the mild, moderate, and severe lung infection groups. Long-term smoking history, β2-MG, and PSGL-1 were risk factors affecting postoperative lung infection in patients with esophageal cancer (P<0.05), and sCHE was a protective factor (P<0.05). The AUCs of serum β2-MG, sCHE, and PSGL-1 for assessing postoperative lung infections were 0.807, 0.845, and 0.800, respectively, and the AUC of the three combined factors for assessing postoperative lung infections was 0.954, which was superior to that assessed individually (Z_{combination vs. β2-MG}=2.576, Z_{combination vs. sCHE}=2.623, Z_{combination vs. PSGL-1}=2.574, all P<0.05). Conclusion The serum levels of β2-MG and PSGL-1 increase and the sCHE level decreases in patients with esophageal cancer and postoperative pulmonary infection, which are also related with lung infection. Combined testing can improve the evaluation value of postoperative pulmonary infection in patients.

In recent years, the burden of chronic and non-communicable diseases has become more serious in China, and the area specific heterogeneities are obvious. Southwestern China is a vast area with many ethnic groups and distinctive characteristics. While the local health resources are relatively limited, and the prevention and control of high-risk chronic diseases is challenging. In order to comprehensively analyze the disease distribution and potential exposure risk in populations in different ethnic groups in southwestern China, a natural population cohort study in southwestern China (multi-ethnic cohort study) was launched in 2017 with the support of the "Precision Medicine Research" Key Project, National Key Research and Development Program of China. At present, this cohort consists of 119 556 participants aged 30-79 years (18-79 years in Tibet Autonomous Region) and pregnant women in five provinces (municipality), i.e. Sichuan, Yunnan, Guizhou, Tibet, and Chongqing. A large-scale, multi-ethnic, high-quality natural population cohort with biobank has been established. The study has made some significant progress in the evaluation of the health impact of environmental and lifestyle factors in southwestern China and developed an innovative model for large cohort establishment in less developed areas. The results of this study can provide a reference for the establishment and research of large natural population cohorts in complex geographical scenarios, and serve as high-quality basic resources for China's precision medicine research and disease prevention and control decisions in areas with multi-ethnic groups.