Fecal Markers Streptococcus Anginosus and Streptococcus Constellatus for Non-Invasive Screening and Early Warning of Gastric Cancer

Background: Most gastric cancer (GC) patients are diagnosed at an advanced stage, which indicates their poor prognosis. We aimed to investigate novel fecal microbial markers for clinical application in the screening and early diagnosis of gastric cancer (GC). Methods: This is an observational study from three cohorts. In discovery cohort, 16S rRNA gene analysis was performed in paired samples (gastric tissues, feces) from GC and CG patients to determine differential microbes. The relative abundances of the differential microbes were detected using qPCR in training cohort. The diagnostic efficacy of fecal marker Sa/Sc was validated in validation cohort. Findings: 575 gastric cancer (GC) patients, 468 chronic gastritis (CG) patients were enrolled from ten hospitals in China. Significant enrichments of Streptococcus anginosus (Sa) and Streptococcus constellatus (Sc) in both cancerous tissues (P < 0·05) and feces ( P < 0·0001) were observed in patients with intraepithelial neoplasia, early and advanced GC. Either the marker parallel test Sa ∪ Sc or single marker Sa/Sc demonstrated superior sensitivity (Sa: 75·6% vs. 72·1%, P