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 FIT, quantitative 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.

Inclusion Criteria:

1. Participants must be at least 18 years of age at the time of enrollment;
2. Participants must be scheduled to undergo gastroscopy and colonoscopy;
3. Participants must agree to undergo a two-year follow-up as outlined in the protocol;
4. Participants must be willing to participate and sign an informed consent form.

Exclusion Criteria:

1. Have undergone gastrointestinal endoscopy screening within the past year;
2. History of any type of gastrointestinal malignancy;
3. Concurrent severe medical conditions that reduce the benefits of screening, such as severe pulmonary disease, kidney disease, liver disease, cardiovascular and cerebrovascular diseases, and hematological disorders;
4. Other situations where a physician determines that endoscopic screening poses excessive risk (e.g., hemodynamic instability) or offers no benefit (e.g., short life expectancy);
5. Pregnant or breastfeeding women.

The study will enroll individuals aged 18 and older who are scheduled to undergo gastrointestinal endoscopy and are willing to participate in the screening.

Once the study is complete, submit a request to the principal investigator. The applicant must provide a data analysis plan, and a decision on whether to share the data will be made following an evaluation.