Background:

- Early detection of colon cancer can improve the chances of successful treatment for most people. This approach is especially important if blood is detected in the stool. However, much better stool sample tests are needed to find this cancer early. To improve the tests, researchers want to collect samples from people who are already being screened for colon cancer. This study will collect information and samples from older adults in Shanghai, China. These adults will be participating in screening tests for colon cancer.

Objectives:

- To collect samples and medical information for colon cancer screening from older adults in Shanghai, China.

Eligibility:

• Adults between 50 and 74 years of age who are being screened for colon cancer.
• Participants will be recruited from two community health centers in Shanghai, China.

Design:

• Participants will provide information on their medical history and factors related to colon cancer. They will respond to questions on use of medications, diet choices (such as eating red meat), bowel habits, and other factors.
• Participants will collect samples for study. These samples will be collected within 3 days of the screening visit. Particpants will provide a urine sample and four stool samples. They will also use cotton swabs to collect samples from just inside the anus. The samples will be returned to the study doctors for research tests that may indicate who has colon cancer.
• Treatment will not be provided as part of this study.

To examine how risk for colorectal cancer (CRC) is related to the microbes that inhabit the distal human intestine (the microbiota), we have proposed a large study that compares characteristics of the fecal microbiota in CRC patients and controls in the Shanghai population. In advance of that, we are proposing a small pilot study with the following two objectives: 1) determine participation rates among Shanghai adults, age 50-74 who are positive by fecal immunochemical test (FIT+); and 2) determine the suitability of fecal specimens provided by the participants for microbiome analyses. Each of two Shanghai community health centers, where CRC screening is ongoing, will recruit 25 FIT+ participants (half male; half age 50-64, half age 65-74). Each of the 50 participants will provide informed consent, brief questionnaire data, blood plasma and buffy coat, a urine specimen, and four samples of one stool, which will be frozen. Complete blood count and plasma glucose, cholesterol, and creatinine levels will be determined in real time and returned to the participant. Each participant s plasma, buffy coat, urine, and one pair of fecal samples will be stored frozen for future genetic or other assays. DNA will be extracted from the second pair of fecal samples from each participant (n=100 vials), amplified for 16S rRNA genes, and sequenced to determine fecal microbiome profiles. Participation will be deemed unsatisfactory if participation is <30% overall (95% confidence interval 17% - 43% for N=50 participants), or if there are <20 male, female, younger, or older participants. Specimen quality will be deemed unsatisfactory if the intraclass correlation coefficient (ICC) is <0.70 (95% confidence interval 0.53 0.82 for N=50 paired vials) for the Shannon index estimate of microbiome alpha diversity. As amended, the two community health centers will recruit up to 600 additional adults presenting for CRC screening, irrespective of FITstatus, who will be asked to provide saliva as well as the other specimens.

• INCLUSION/EXCLUSION CRITERIA:

Participation is restricted to adults age 50-74 who are: 1) residents of the catchment areas of the community health centers in Shanghai s Minhang and Xuhui Districts, and 2) are participating in the CRC screening program at those centers. Patients who do not provide signed informed consent will be excluded.