Cytokine-induced killer cells (CIK) is an auxiliary antitumor treatment. The investigators aim to evaluate the clinical efficacy of chemotherapy combined with CIK in the treatment of postoperative colorectal cancer patients. And to provide useful reference for the clinical application of CIK in colorectal cancer patients.

Over the past decade, advances in combination chemotherapy regimens for colorectal cancer have led to significant improvement in progression-free and overall survival. Cytokine-induced killer cells (CIK) is an auxiliary antitumor treatment. Research has demonstrated the median overall survival (OS) in patients received CIK combined with chemotherapy (5-Fluorouridine, leucovorin and oxaliplatin [FOLFOX4] plan) was significantly increased compared with that in patients received chemotherapy alone. Furthermore, there was a trend toward superior progression-free survival time (PFS) in patients received CIK combined with chemotherapy compared with that in patients received chemotherapy alone. The investigators aim to evaluate the clinical efficacy of chemotherapy (FOLFOX4) combined with CIK in the treatment of postoperative colorectal cancer patients. And to provide useful reference for the clinical application of CIK in colorectal cancer patients.

Inclusion Criteria:

1. Tumor, Nodes, Metastasis (TNM) stage of II or III;
2. Patients received radical resection of colon cancer;
3. Pathological diagnosis of adenocarcinoma;
4. Patients not received radiotherapy and chemotherapy before surgery;
5. The preoperative examination confirmed without systemic metastasis;
6. Patient has the Karnofsky score more than 70 points;
7. Subjects signed informed consent.

Exclusion Criteria:

1. Patients who was serious allergy to any of the ingredients of drugs used in this study;
2. Patients who unable to comply with the treatment plan or research program;
3. Patients with severe systemic disease that the researchers judged will be unable to complete the study;
4. Patients have severe heart disease, such as myocardial infarction within 6 months;
5. Patients who have received chemotherapy or systemic antitumor therapy (such as monoclonal antibody therapy);
6. Patients received radiotherapy;
7. Having other malignant tumors in the last 5 years, but not including who has been cured through surgery and survived 5 year of disease-free;
8. Any unstable systemic diseases (including active infection, uncontrolled hypertension, unstable angina, congestive heart failure, or myocardial infarction, serious arrhythmias, liver, kidney or metabolic diseases within six months).
9. Patients who do not get effective treatment of inflammation, eye infections or predisposing factors;
10. Physical examination or laboratory findings evidence reasonable doubt who is ill or use of related drugs could affect the study;
11. Patients with serious active infections;
12. Woman who are pregnant or lactating.

whether individual participant data (IPD) could be shared must obtain the consent of the subjects