Gastric cancer has a very poor prognosis. The disease is often diagnosed at a late stage, when curative treatment options are limited or ineffective. There is a condition that predisposes to gastric cancer, known in medical terms as Gastric intestinal metaplasia (GIM). This pre-cancerous condition can be diagnosed with an endoscopic camera test, but it often very subtle and can be missed at routine endoscopy. There is evidence that about 7% of gastric cancers are missed at previous endoscopy. The Cytosponge-trefoil factor 3 (TFF-3) is a pill on a string combined to a molecular biomarker which could help early diagnosis of gastric cancer and GIM. Cytosponge-TFF3 has been showed in previous research to be useful to diagnose Barrett's oesophagus, a condition of the food pipe similar to GIM. The aim of this study is to investigate the utility of the Cytosponge in combination with molecular biomakers to diagnose GIM