Study on  salivary and fecal microbial diversity in patients with colorectal polyps
We aimed to investigate the differences in salivary and fecal microbiota between patients with colorectal polyps and healthy controls to identify novel noninvasive biomarkers for colorectal polyps. Salivary samples were collected from all subjects in the morning. Subjects were instructed not to eat, drink, smoke, or perform any oral hygiene procedures 2 hours before sampling. The participants gargled with deionized water and collected unstimulated saliva in a plastic cup. If blood was present in the saliva, it was discarded and collected again. The supernatant was collected and divided into Eppendorf tubes, which were immediately stored at minus 80degrees. Repeated freeze-thawing of salivary samples were avoided during the study. For all subjects, approximately 5g fresh fecal specimens from the middle section were collected using a special fecal kit (Shanghai Personalbio Technology Co, Ltd, Shanghai, China), immediately frozen at minus 20degrees, stored in a dry ice box and transported to the laboratory, and stored at minus 80degrees until further analysis.