Development of Novel Gastric Cancer Screening and Diagnosis Technologies Using Tongue Imaging and Study of Tongue Image Changes Mechanisms

Inclusion Criteria for Gastric Cancer Patients: * 18≤age≤90 * Histologically or cytologically confirmed gastric cancer * No prior chemotherapy, radiotherapy, biotherapy, immunotherapy or other anti-tumor treatment for gastric cancer * Subject volunteers to join the study, Signs informed consent, has good compliance and can cooperate with follow-up Exclusion Criteria for Gastric Cancer Patients: * Two or more kinds of malignant tumors at the same time * Gastric cancer that has been treated by chemotherapy, radiotherapy, biotherapy, immunotherapy or other anti-tumor therapy * The use of glucocorticoids and antibiotics in the past three months * History of long-term medication * Presence of oral diseases such as tooth and gum diseases * 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 Inclusion Criteria for Healthy Participants: * 18≤age≤90 * Willingness to participate in the study, signing an informed consent form, and demonstrating good compliance Exclusion Criteria for Healthy Participants: * History of malignant tumors * The use of glucocorticoids and antibiotics in the past three months * History of long-term medication * Presence of oral diseases such as tooth and gum diseases * 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