Gastric and colorectal cancers (GC and CRC) have poor prognosis and are resistant to chemo- and/or radiotherapy. In the
present study, the prophylactic effects of dendritic cell (DC) vaccination are evaluated on disease progression and clinical
benefits in a group of 54 GC and CRC patients treated with DC immunotherapy combined with cytokine-induced killer (CIK)
cells after surgery with or without chemo-radiotherapy. DCs were prepared from the mononuclear cells isolated from
patients using IL-2/GM-CSF and loaded with tumor antigens; CIK cells were prepared by incubating peripheral blood
lymphocytes with IL-2, IFN-c, and CD3 antibodies. The DC/CIK therapy started 3 days after low-dose chemotherapy and was
repeated 3–5 times in 2 weeks as one cycle with a total of 188.3679.86106 DCs and 58.8622.36108 CIK cells. Cytokine
levels in patients’ sera before and after treatments were measured and the follow-up was conducted for 98 months to
determine disease-free survival (DFS) and overall survival (OS). The results demonstrate that all cytokines tested were
elevated with significantly higher levels of IFN-c and IL-12 in both GC and CRC cohorts of DC/CIK treated patients. By Cox
regression analysis, DC/CIK therapy reduced the risk of post-operative disease progression (p,0.01) with an increased OS
(,0.01). These results demonstrate that in addition to chemo- and/or radiotherapy, DC/CIK immunotherapy is a potential
effective approach in the control of tumor growth for post-operative GC and CRC patients.