Distribution of esophagus flora in esophageal squamous cell carcinoma and its correlation with clinicopathological characteristics

BACKGROUND: Esophageal cancer is one of the most common malignant tumors in the digestive system in China. However, the specific pathogenic factors and mechanisms of esophageal cancer are not yet clear. Here, the distribution of esophageal flora in esophageal squamous cell carcinoma (ESCC) and its correlation with clinicopathological characteristics are analyzed. METHODS: Fifty-four patients with ESCC diagnosed in our hospital from June 2018 to January 2020 were selected. The patients’ gender, age, course of the disease, the grade of pathological tissue, and degree of differentiation were recorded. The distribution of esophageal mucosa flora in patients with ESCC and significant esophageal flora in the esophageal mucosa of different patients were compared. RESULTS: At the genus level, Proteus, Firmicutes, Bacteroides, and Fusobacterium are the main dominant bacteria in esophageal cancer tissues. At the subordinate level, Prevotella, Clostridia, Streptococcus, Delftia, Klebsiella, Serratia, and some unclassified florae belong to the dominant species. Furthermore, there were no significant differences in the abundance of bacteria between the esophageal cancer tissues and the normal cancerous tissues (P>0.05). Also, there was no difference in the diversity of bacterial flora in ESCC tissues of different parts, different morphology, different staging, and different lymph node metastasis (P>0.05). The abundance of Firmicutes, Proteobacteria, and Bacteroides was significantly higher than Clostridia. Furthermore, Actinobacteria and Spirochaetae had the lowest abundance of Spirochaetae. The abundance of Spirochaetae of ulcerative type was significantly higher than medullary type ESCC, while the abundance of Actinobacteria of both medullary and ulcerative types was significantly lower than other types (P<0.05). There were no significant differences in esophageal flora abundance in different tumor stages of esophageal cancer mucosal tissues (P>0.05). The abundance of Proteobacteria was significantly reduced with the presence of lymph node metastasis, while Bacteroides abundance increased significantly (P<0.05). CONCLUSIONS: There are individual differences in the distribution of esophageal flora for ESCC. The diversity and distribution of esophageal tissues are reduced and disordered compared to normal esophageal tissues. There are no correlations between distinct parts and stages of ESCC and esophageal flora, while morphological types and lymph node metastasis can affect the structure of esophageal flora.