Microbiome associations between esophageal adenocarcinoma and esophageal squamous cell carcinoma.

Abstract

e16050 Background: Microbiomes in tumor environment are thought to be associated with outcomes of precision therapy. Esophageal squamous cell carcinoma (ESCC) and Eophageal adenocarcinoma (EA) are the two subtypes of esophageal cancer. Although gene mutation and expression profiles have been well characterized, the microbial set between them are poorly studied. Methods: The microbial dataset of the identified species and their relative abundance using whole genome sequencing (WGS) and whole exome sequencing (WES) was obtained from TCMA database, which includes 17 EA samples and 32 ESCC samples. To investigate the microbial difference between EA and ESCC, The alpha diversity (Shanno and Simpson index) and beta diversity (PCoA, NMDS, Adonis) were calculated using the identified species to examine the overall difference between the two subtypes. The student's t-test were used to examine the relative abundance of single species Using the identified differential abundant microbial species, correlation analysis were performed to investigate whether synergistic effects exist for some species between the two subtypes. Moreover, taxonomy set enrichment analysis was used to find out whether the differential genus between EA and ESCC were associated with cancers. Finally, cox regression was used to investigated differential species between EA and ESCC affected the survival rate of EA group or ESCC group. Results: Through alpha and beta diversities, we didn’t find overall difference between EA and ESCC both in WGS and WES datasets. However, seventeen and two differential abundance species were found using Student’s t-test in WGS and WES datasets, respectively. The relative abundances of the differential species were mostly higher in ESCC than in EA. Correlation analyses showed that prevotella sp. HMSC069G02 and prevotella sp. HMSC077E08 were highly correlated. There were eight differential species ( prevotella aurantiaca, prevotella dentalis, prevotella marshii, etc.) were found in WGS and two species ( prevotella sp. C561, prevotella pleuritidis) in WES, respectively. The ten species all belong to prevotella genus, and taxon set enrichment analysis showed prevotella genus was associated with esophageal cancer, implies the identified differential species may be different in ESCC and EA patients. Among them, prevotella dentalis and prevotella buccae were found to be potentially risk factors in ESCC after Cox regression. Conclusions: This study investigated the microbiome difference between EA and ESCC cancers. Although we didn’t find the overall difference between the two subtypes, our preliminary results showed there exist some differential species between two subtypes. We found prevotella dentalis and prevotella buccae were the potential risk factors in ESCC, and the results can help further understand the therapy outcome differences between EA and ESCC from the microbial aspect.