This is a prospective, multi-center, observational cohort study and seeks to enroll 20000 patients with one malignant tumor of digestive tract or healthy individual.

This study collected tongue coating samples non-invasively and analyzed the tongue coating metaproteomics, metagenomics and metabolomics profiles of patients with gastrointestinal malignancies.

The performance characteristics(sensitivity and specificity) of tongue coating morphology, metaproteomics, metagenomics and metabolomics tests for detection of gastrointestinal malignancies are evaluated in comparison to pathology.

Inclusion Criteria:

18≤age≤80.

Histologically or cytologically confirmed malignant tumor.

No prior chemotherapy, radiotherapy, biotherapy, immunotherapy or other anti-tumor treatment for malignant tumor.

Subject volunteers to join the study, signs informed consent, has good compliance and can cooperate with follow-up.

Exclusion Criteria:

Two or more kinds of malignant tumors at the same time.

Malignant tumor that has been treated by chemotherapy, radiotherapy, biotherapy, immunotherapy or other anti-tumor therapy.

Subjects who had other factors that might force them to terminate the research ahead of time, such as the development of other severe disease (including mental disease) that required combined treatment, seriously abnormal laboratory examination value, and family or social factors that might affect the subject safety or experimental data collection, as judged by the researchers.

Histologically or cytologically confirmed digestive tract malignant tumor，and no prior chemotherapy, radiotherapy, biotherapy, immunotherapy or other anti-tumor treatment for malignant tumor.