This study constitutes a case-control investigation employing a retrospective approach. Plasma samples from individuals with esophageal cancer, benign esophageal diseases, gastric cancer, benign gastric diseases, and a healthy control group were systematically collected. Advanced Data-Independent Acquisition (DIA) proteomics and single-vesicle membrane protein detection techniques were employed to quantify protein content within exosomes. Specific protein biomarkers indicative of early-stage upper gastrointestinal tumors were identified. External validation of these protein markers was conducted using Parallel Reaction Monitoring (PRM) technology on an independent validation cohort. The objective is to establish protein marker predictions for early diagnosis of upper gastrointestinal tumors and prognostication of therapeutic efficacy.