RESUMO
Objective:To investigate the esophageal microecology in patients with esophageal carcinoma (EC), and to compare the difference in esophageal flora between patients with esophageal cancer and healthy people.Methods:From July 2018 to July 2019, at Taihe Hospital, 82 EC patients and 20 age-and gender-matched healthy controls during the same period were selected. The pathology of EC were divided into poorly differentiated (8 cases), moderately differentiated (9 cases) and well differentiated cancers (13 cases) according to the degree of differentiation. The esophageal tissue samples of EC patients and healthy individuals were collected. Sample DNA was extracted and the V4 region of bacterial 16S rRNA was amplified by polymerase chain reaction (PCR). Sequencing was performed by lllumina HiSeq 4000 sequencing platform. Alpha-diversity analysis and principal co-ordinates analysis (PCoA) were performed, and linear discriminant analysis (LDA) of linear discriminant analysis effect size (LEfSe) was used to screen different species. The random forest model was verified by receiver operating characteristic (ROC) curve and the esophageal bacterial phenotype was predicted by BugBase database. Non-parametric Kruskal-Wallis H test and Wilcoxon rank sum test were used for statistical analysis. Results:The Chao1 index of the EC patients was higher than that of healthy controls (362.51(284.29, 646.13) vs. 284.83(244.31, 344.74)), and the difference was statistically significant ( Z=-2.857, P=0.004). The results of PCoA showed that the distance between samples of EC patients and healthy control samples was relatively close, and there was no significant difference in the composition of microecology between the two groups ( P>0.05). The abundance of esophageal Cyanobacteria and Verrucomicrobia of EC patients were both higher than those of healthy controls (0.2% vs. 0.1%, 0.4% vs. 0), while the abundances of esophageal Proteobacteria, SR1 and TM7 phylum of EC patients were lower than those of healthy controls (21.9% vs. 34.2%, 0.1% vs. 0.2%, 0.2% vs. 0.5%), and the differences were statistically significant ( Q=0.090, 0.077, 0.010, 0.026 and 0.001, all P<0.05). The abundances of Clostridia, Elostridiales, Pasteurella, Pasteurellaceae, Eikenella, Actinobacillus and Haemophilus in poorly differentiated patients, moderately differentiated and higher differentiated patients were 28.3%, 24.2% and 17.0%, 28.3%, 24.2% and 17.0%, 3.2%, 0.3% and 5.0%, 3.2%, 0.3% and 5.0%, 0, 1.5% and 0.1%, 0.5%, 0 and 0.7%, 1.3%, 0.2% and 3.9%, respectively, and the differences were statistically significant ( Q=0.579, 0.557, 0.390, 0.711, 0.768, 0.768 and 0.768, all P<0.05). LEfSe analysis showed that the abundances of Fusobacterium, Ruminococcus, Odorbacterium and S24_7 of EC patients were higher than those of healthy controls (21.5% vs. 11.7%, 0.5% vs. 0.1%, 0.1% vs. 0 and 0 vs. 0), and the differences were statistically significant (LDA=2.591, 2.379, 2.790 and 2.927, all P<0.05). The ROC curve confirmed that the random forest model was reliable and the AUC value was 0.92. BugBase database phenotypic prediction showed that the phenotype of esophageal bacteria related to biofilm formation, pathogenic potential, mobile elements, oxygen demand (aerobic, anaerobic and facultative bacteria), and oxidative stress tolerance of EC patients were more abundant than those of healthy controls (all P<0.05). Conclusions:The esophageal flora of patients with esophageal cancer has changed. Fusobacterium, Ruminococcus, Odoribacterium and S24_7 may be potential biomarkers of esophageal flora.