Detecting circulating tumor cells from I-IV stage colorectal cancer patients pre-and post-operatively. Analyzing the morphology and biomarkers of CTCs and builting prognosis predicting model based on the morphology and biomarkers of CTCs. Verifying the prognosis model by the survival data.

Inclusion Criteria:

• Age 18-80 years;

Histologically proven colorectal carcinoma (TNM stage I-IV)

R0 resection is possible according to preoperative evaluation

Written informed consent for participation in the trial.

Exclusion Criteria:

• Primary tumor or metastases not able to be removed radically

Receiving any preoperative treatment (Including chemotherapy, radiotherapy and target therapy)

Have other malignant tumors meanwhile

Other previous malignancy within 5 years

I-IV stage colorectal cancer patients with resectable lesion(s) who not receive preoperative treatment