INTRODUCTIONGastrointestinal disorders are common diseases and can be diagnosed by endoscopy as a simple and effective procedure. Endoscopy has become a gold standard diagnostic procedure. The main goal of the endoscopist is to early diagnose or exclude gastrointestinal cancer and other gastrointestinal diseases. Carcinoembryonic antigen (CEA), carbohydrate antigen 19-9 (CA 19-9), and alpha fetoprotein (AFP) are used as markers of gastrointestinal malignancies [1]. CA 19-9 and CEA are antigens linked to most cancers of epithelial origin, including gastrointestinal cancers [2]. Serum levels of CEA and CA 19-9 are increased in precancerous lesions and early stages of cancer. Also in a recent study, which was proposed to us, on the measurement of CEA and CA 19-9 in gastric juice by an endogastric capsule, we can distinguish precancerous lesions from cancers or normal cases [3]. The most commonly used tumor markers; CA 19-9, CEA and AFP are not a beneficial screening method [4]. We aimed to investigate the relationship between endoscopy-diagnosed gastrointestinal disorders and serum tumor marker levels. Evidence of increased serum tumor marker levels may be an urgent indicator for endoscopy in dyspeptic patients.MATERIALS AND METHODSIn this study, we compared serum tumor marker levels of patients admitted to Sivrihisar Public Hospital with gastrointestinal system symptoms and who underwent upper gastrointestinal endoscopy with a control group. healthy volunteers. This study was authorized by the local ethics committee. In this way, serum levels of CA 19-9, CEA and AFP were examined in forty patients who underwent endoscopy and forty healthy volunteers. Collection of 5 ml of blood from all patients and subsequent 20-minute collections middle of paper ......n patients with resectable gastric carcinoma: comparison with CEA. J Surg Oncol. 2001;76:266-271.14. Iwasaki Y, Arai K, Katayanagi S, Takahashi K, Yamaguchi T, Matsumoto H et al. Biomarkers of neoplasms of the digestive organs. Gan in Kagaku Ryoho 2004; 31:1015-1020.15. Micali B, Florio MG, Venuti A et al. Usefulness of measuring carcinoembryonic antigen in gastric juice of patients with gastric disorders. J Clin Gastroenterol 1983; 5: 411-415.16. Farinati F, Nitti D, Cardin F et al. Determination of CA 19-9 in gastric juice: role in the identification of gastric cancer and high-risk patients. Eur J Cancer Clin Oncol 1988; 24:923-927.17. De Vries AC, van Grieken NC, Looman CW, Casparie MK, de Vries E, Meijer GA, Kuipers EJ. Risk of gastric cancer in patients with precancerous gastric lesions: a nationwide cohort study in the Netherlands. Gastroenterology 2008;134:945-952.