The aim of the study is to identify and verify one or more gut bacteria of which the abundance in feces may help to early diagnosis colorectal cancer.

Gut microbiota is closely related to human gut neoplasm. According to recent statistics, the abundance of FN (Fusobacterium Nucleatum) is connected with the development and progression of CRCs (colorectal cancers). Subsequent research shows identifying multiple microbial-specific genes in human feces using qPCR (quantitative Polymerase Chain Reaction) may help diagnosis of early stage colorectal cancer. Currently little is known about the relationship between single abundance of specific gut microbiota and colorectal cancer in different stage. Moreover, finding early-stage CRCs is still of great challenge partially due to precancerous diseases like colorectal adenoma which remain difficult to differentiate from early-stage CRC under endoscope. Conventional clinic methods predicting CRCs largely depend on serum CEA (serum Carcino Embryonic Antigen) and OB(fecal occult blood test), which lack of adequate sensitivity and specificity especially in early stage CRCs. The investigators' work focuses on the abundance of gut microbiota in feces from people with colon neoplasm and its comparison with classical indicators such as CEA and OB, aiming to reveal and testify its potential role on assisting diagnosis of CRCs in different stage as a none-invasive cost-effective method.

Inclusion Criteria:

• Patients age from 40 to 85 years old
• Patients with endoscopic or pathological confirmed healthy, adenoma, inflammation, early or late stage of colorectal cancer
• Patients with valid CEA(carcino embryonic antigen) and OB(occult blood) test result in 1 year before or after the coloscopy or surgery

Exclusion Criteria:

• Patients with history of colorectal cancer
• Patients with long term use of antibiotics or probiotics
• Patients with uncontrolled diabetes, hypertension or hepatitis
• Patients with a history of subtotal gastrectomy or partial bowel resection
• Patients who are not able to cooperate
• Patients with medical conditions who are not appropriate to participate the study
• Patients who are taking aspirin, NSAIDs (nonsteroidal antiinflammatory drugs), COX2(cyclo-oxygen-ase 2) inhibitors.

Chinese people