This study is a multi-center, observational study. Participants scheduled for gastroscopy and colonoscopy will undergo an epidemiological assessment and provide a stool sample prior to endoscopy for qualitative Fecal Immunochemical Test (FIT), quantitative Fecal Immunochemical Test (FIT), and novel biomarker testing, followed by the endoscopic examination. After completion of the baseline endoscopic screening, all enrolled participants will undergo a 2-year follow-up. The primary endpoints of the study are sensitivity and specificity for the screening of gastrointestinal cancers.The aim of this study is to develop and evaluate the sensitivity and specificity of fecal multi-marker panels for the screening of gastrointestinal cancers.