Gastric and oesophageal (OG) cancer associated with poor long term outcome as overall less than 25% of patients survive for more than 5 years due to late recognition of the disease. Growing evidence suggests an important role for bacteria in OG cancer and gastro esophageal reflux disease (GORD) development. About 1 in 10 people suffer from GORD and this one of the most common conditions leading to gastric and oesophageal cancer.

In GORD surgical therapy is the most successful preventing cancer but around 85% of patient experience complications afterwards. Acid suppressing medications are reducing the risk of oesophageal cancer but equally increasing the risk of gastric cancer. They also shorten patients' life expectancy and often fail to provide relief. Analysis of stool samples of patients with GORD demonstrated different gut bacterial compositions to normal and rather resembled the one found in cancer.

There is a clear need to improve the outcome of OG cancer. This could be achieved by identifying bacteria responsible for cancer development in gastric tissue, gastric content and saliva and potentially eliminate them hence avoid the development of cancer.

Inclusion Criteria:

• Patients who deemed necessary for an upper gastro intestinal endoscopy for clinical reasons and consent for additional gastric mucosal biopsies for study purposes

Exclusion Criteria:

• Patients who have upper GI malignancy

Patients with erosive, non-erosive reflux and patients with no symptoms of reflux and healthy upper GI mucosa.