The Diagnostic Value of Nitrogen Element (N) in Esophagus Cancer

Inclusion Criteria: * Esophageal cancer patients (Case): Subject diagnosed with ESCA based on typical clinical symptoms, endoscopic observation of esophageal lesions, and histopathological examination of biopsy specimens obtained from the lesion sites. * Reflux esophagitis patients (Case control): Subject diagnosed diagnosed with reflux esophagitis based on typical clinical symptoms (e.g., heartburn and acid regurgitation) and endoscopic evidence of esophageal mucosal injury classified according to the Los Angeles classification system (Grade A: mucosal breaks ≤5 mm in length; Grade B: mucosal breaks \>5 mm in length but not confluent; Grade C: confluent mucosal breaks involving \<75% of the esophageal circumference; Grade D: confluent mucosal breaks involving ≥75% of the esophageal circumference). * Health people: (Healthy control): no history of malignant tumors within the past five years, normal findings on gastroscopy, with no evidence of esophageal or gastric lesions, no history of gastrointestinal diseases such as gastroesophageal reflux disease (GERD) or Barrett's esophagus, blood counts, tumor biomarkers, and liver and kidney function tests within normal ranges. Exclusion Criteria: * Esophageal or gastric surgery * History of previous upper abdominal surgery * History of previous gastrectomy, endoscopic mucosal resection or endoscopic submucosal dissection * History of other malignant disease within past five years * History of previous neoadjuvant chemotherapy or …