Potential role of dendritic cell vaccination with MAGE peptides in gastrointestinal carcinomas

Dendritic cells (DCs) loaded with tumor antigens have been emerging as a new strategy in cancer treatment. The MAGE genes are selectively expressed in a variety of cancer tissues such as melanoma or gastrointestinal carcinomas. However, no expression is observed in normal tissues except testis. There are several reports on clinical trials with these immunogenic peptides including MAGE gene-derived, which were shown to be effective for some patients with carcinomas. We previously reported a clinical trial treating gastrointestinal carcinoma patients with immature DC and MAGE peptides via intravenous injection. Autologous DCs were generated ex vivo and were pulsed with MAGE-3 peptide, depending on the patient's HLA haplotype (HLA-A02 or A24). In this study, patients were immunized with mature DCs pulsed with the MAGE-3 peptide four times every 2 weeks via s.c. injection close to the axilla and inguinal lymph nodes. Twenty-eight patients with advanced gastrointestinal carcinoma were treated and no toxic side effects were observed. Peptide-specific CTL responses, improvement in performance status, tumor marker decrease and minor tumor regressions after vaccination were observed in some patients. These results suggested that DC vaccination with the MAGE-3 peptide would be safe and can exhibit antitumor effects even in the patients with advanced gastrointestinal carcinoma who were previously treated with chemotherapy or radiation therapy.