Biomarkers in Gastric Cancer: Blood Biomarkers, Liquid Biopsy, Artificial Intelligence, and Risk-Stratified Care

Gastric cancer is often diagnosed in advanced stages for patients in countries without organized screening processes. Non-invasive biomarkers have been proposed to risk-stratify and identify those who should undergo endoscopy.

We searched PubMed/MEDLINE, Scopus, and Google Scholar for studies published between January 2006 and May 2026 reporting diagnostic accuracy or health-economic outcomes for gastric cancer detection in asymptomatic adults or patients with precursor mucosal lesions. Twenty-five studies met eligibility criteria and were synthesized narratively, with reporting informed by PRISMA-DTA and Ferrari guidance.

Systemic inflammatory indices derived from routine blood counts are inexpensive but non-specific, with individual areas under the receiver operating characteristic curve (AUC) between 0.65 and 0.83. Serological markers of mucosal atrophy have a clearer biological basis and carry the review's only large Western validation dataset but preferentially detect corpus-predominant disease. Liquid biopsy platforms report the highest accuracy, up to an AUC of 0.968, though sensitivity falls to 62.4% for precancerous lesions and to 44% for stage I disease on some platforms. Magnifying narrow-band imaging reported the highest accuracy among the endoscopic modalities reviewed, with an AUC of 0.97. In low-incidence Western settings, one-time serum pepsinogen screening with endoscopy reserved for positive results is cost-effective at USD 4913 per QALY gained.

Reported accuracy is encouraging across all four classes of gastric cancer markers but derives mainly from retrospective East Asian case-control cohorts and declines at the earliest stages of disease. The evidence supports using these markers to triage toward endoscopy rather than to diagnose directly. Validation in Western populations remains a gap.