The aim of this observational study is to comprehensively analyze the metabolites in plasma samples from gastric cancer patients using advanced mass spectrometry detection technology, in conjunction with both broad-spectrum and targeted metabolomics approaches. The goal is to construct a dedicated plasma metabolite database for gastric cancer patients. Simultaneously, we will delve into the exploration and validation of a series of metabolic biomarkers for early gastric cancer diagnosis. The objective is to establish a safer, more convenient, and more sensitive early screening method, thereby providing a reliable scientific foundation and critical evidence for improving the early diagnostic process for individuals at high risk of gastric cancer.

Firstly, a wide-targeted metabolomic measurement will be conducted on plasma samples from the discovery cohort to identify potential metabolite candidate markers and construct a gastric cancer patient-specific metabolite database with extensive metabolite information.

Secondly, a more precise targeted metabolomic measurement will be conducted in the modeling cohort. Bioinformatics methods will be used to conduct an in-depth analysis of a wide range of metabolite information to screen out metabolic marker combinations with high gastric cancer-specific diagnostic efficacy.

Ultimately, an external validation cohort will be introduced to validate these metabolic biomarkers, aiming to ensure reliability and stability across different patient populations.

Inclusion Criteria:

• Confirmed diagnosis of gastric cancer or benign gastric diseases through gastroscopy and pathological examination.
• Collection of plasma samples prior to surgical treatment.
• Availability of complete clinical data.

Exclusion Criteria:

• Previous reception of anti-tumor treatments (including radiotherapy, chemotherapy, etc.) before blood collection.
• Coexistence of other systemic tumors.
• Absence of plasma sample collection before surgical treatment.
• Incomplete clinical data.
• Pregnancy status.

The study population included a range of subjects with gastric and non-gastric cancer, including patients with benign gastric disease and healthy controls, who were admitted to the main study center and other collaborating sub-center hospitals.