A microbiome marker for gastric cancer. The present invention relates to a method for distinguishing a gastric cancer from a preneoplastic benign condition by detecting a nucleic acid or a metabolite derived from a specific bacterium. The mentioned method uses a reaction composition comprising primers for the detection and amplification of a reaction with the nucleic acid of the particular bacterium or a metabolite derived from a metabolic function. Another aspect of the invention is a primer used in the practice of the above method with sequences showing high specificity for said particular bacterial nucleic acid (identified as SEQ ID NO: 1 to SEQ ID NO: 18), and It relates to a composition comprising a primer. The invention further relates to a kit comprising the composition described above for detecting nucleic acids or metabolites from a particular bacterium by carrying out the method of the invention. The methods, gene sequences, compositions and kits of the present invention may be advantageously used for distinguishing gastric cancer from preneoplastic benign conditions in biological samples, which comprises the methods, gene sequences, Due to the high sensitivity and specificity of such compositions and kits for such discrimination. Accordingly, the present invention may be applied in the monitoring of patients with preneoplastic benign conditions (eg, chronic gastritis, intestinal metaplasia and dysplasia) to detect or predict the occurrence of gastric cancer. In particular, it can provide the basis for proper treatment settings. Therefore, the present invention is included in the technical fields of medicine, pharmacy, molecular biology, biochemistry, and bacteria-related genetics. [Selection diagram] None【課題】胃癌用のマイクロバイオームマーカーに関する。【解決手段】本発明は、特定の細菌に由来する核酸又は代謝産物の検出により、新生物発生前の良性状態から胃癌を識別するための方法に関する。言及した方法は、前記特定の細菌の核酸又は代謝機能に由来する代謝産物との反応物の検出及び増幅用のプライマーを含む反応組成物を使用する。本発明の別の態様は、前記特定の細菌の核酸に対して高い特異性を示す配列（配列番号１～配列番号１８として識別される）による上述した方法の実施で使用されるプライマー、及びこのプライマーを含む組成物
