Many studies demonstrate that microbial dysbiosis has been linked to many human pathologies. However, the current understanding of the identification of the disease-associated microbiome signatures remains limited, largely owing to the heterogeneity of microbial community structures which are shaped by the host. Undoubtedly, profiles of microbial biomarkers require validation in large, independent, population-based cohorts from different districts. Based on these, the investigator plan to organize a multicentric cross-sectional cohort, not only to systematically characterize the gut microbiota of various critical chronic diseases, such as liver cancer, gastric cancer, pancreatic cancer, lung cancer, nasopharyngeal cancer, hypertension, acute coronary syndrome, primary aldosteronism, epilepsy, chronic kidney disease, and subclinical hypothyroidism but also to compare the similarities and differences of the microbiome signatures linked to different regions and different diseases and to further investigate their impacts on microbiota-based diagnostic models. In this study, for each kind of disease, the investigators expect to recruit 500 patients with a confirmed diagnosis and 500 sex- and age-matched controls, to record their information related to demography, body measurement, lifestyle, diet, medication, diseases, and biochemistry, and to collect their feces, saliva, urine and blood samples.