Poster Presentation 29th Lorne Cancer Conference 2017

Altered esophageal microbiome in Barrett’s esophagus and esophageal adenocarcinoma (#240)

Thi-My-Tam Nguyen 1 , Erin Shanahan 1 2 3 , Lutz Krause 1 , PROBE NET , Andrew Barbour 3 , Mark Morrison 1 , Michelle Hill 1
  1. The University of Queensland Diamantina Institute, The University of Queensland, Translational Research Institute, Brisbane, Queensland, Australia
  2. Department of Gastroenterology and Hepatology, Princess Alexandra Hospital, Brisbane, Queensland, Australia
  3. School of Medicine, The University of Queensland, Brisbane, Queensland, Australia

Background

Esophageal adenocarcinoma is a relatively rare cancer that has been rapidly increasing in incidence. While the risk factors for esophageal adenocarcinoma have been well investigated; the causal relationship between the risk factors and cancer remains unclear and the cause for such a rapid shift in malignant progression is unknown. It is hypothesized an environmental factor may play a role in the increase in incidence and the microbiome may be the missing link.

Rationale

To date no more than a handful of studies have looked at the microbiome in esophageal disease using culture-independent methods and none in esophageal adenocarcinoma. We are the first to investigate the microbiome in esophageal adenocarcinoma and its correlation with premalignant conditions gastroesophageal reflux disease and Barrett’s esophagus using culture-independent techniques.

Method

Samples were generously provided by PROBE-NET and A/Prof Andrew Barbour. Samples used were biopsies from gastroesophageal reflux disease patients (n=10), squamous (n=10) and columnar (n=10) esophageal tissues from Barrett’s esophagus patients, and normal stomach (n=10) and tumor tissues (n=10) from esophageal adenocarcinoma patients. Genomic DNA extracted from the biopsies were sequenced (Illumina MiSeq) and assessed by 16S rRNA gene analysis using QIIME1 and Calypso2.

Results

Microbiome results showed with disease severity there was an increase in Gram-negative species and a decrease in Gram-positive species. The results agree with current literature by Yang et al which suggests normal esophagus is predominated by gram-positive bacteria, and premalignant conditions such as reflux esophagitus and Barrett’s esophagus have a greater proportion of gram-negative bacteria3.

Conclusion

Although studies investigating microbiome in esophageal disease is limited, our studies suggests diverse bacterial communities may be associated with esophageal disease as bacterial composition differs under conditions of reflux disease, Barrett’s esophagus and esophageal adenocarcinoma. As esophageal microbiology is an understudied field, microbiome studies open new possibilities to understanding the etiology and microbial pathogenesis of esophageal disease.

  1. QIIME: http://qiime.org/tutorials/tutorial.html
  2. Calypso: http://cgenome.net:8080/html/wiki/index.php/Calypso
  3. Yang et al. 2009 Gastroenterology 137(2):588-597