Many studies have shown a significant change of diversity and composition in gut microbiota across the gastric carcinogenesis process, particularly in patients with gastric cancer. However, there has been no analysis of gastric microbiota using the mucosal brushing technique, despite its favoring benefit in microbiota study. Therefore, this study aims to evaluate microbiota profile in patients with gastric cancer, compared to those without gastric cancer by using mucosal brush sampling. This will improve current knowledge of the potential role of the microbiome in patient gastric cancer as a future biomarker marker using brushing sampling.