Colorectal cancer (CRC) is one of the most common malignant tumors in the world. Most of the patients with colorectal cancer were diagnosed in poor stage. Although 40% to 50% patients of colorectal cancer can be cured by surgery, but most patients have undergent metastasis or recurrence, and eventually death. In recent years, molecular targeted therapy has shown significant efficacy in specific patients. It was necessary to detect the corresponding molecular targets of tumors before selecting appropriate targeted drugs in clinic. The changing state of related gene molecules in colorectal cancer played a key role in drug selection, there were few effective targets so far. At present, metastasis and recurrence still be the most difficult problems in treatment. Therefore, investigators should deeply study the occurrence and development of colorectal cancer at the gene level and look for new biomarkers to predict the prognosis. Furthermore, the study can clarify the exact molecular mechanism of colorectal cancer. These will be important clinical significance for targeted therapy of colorectal cancer.

Inclusion Criteria:

1.18-80 years old.

2.18.5 < BMI < 27.9.

3. The surgical methods are radical resection of rectal cancer, resection of right colon cancer, resection of left colon cancer and radical resection of sigmoid colon cancer.

Exclusion Criteria:

1. Those who refuse to collect samples.
2. Patients with severe dysfunction of coagulation, hepatorenal dysfunction or severe cardiopulmonary diseases.
3. Patients who has a history of neoadjuvant radiotherapy or chemotherapy.
4. Combining with distant multiple metastases of tumor

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