In our recent phase II trial for adjuvant cancer-specific oncoantigen peptide vaccine for esophageal cancer patients who had neoadjuvant chemo(radiation)therapy and curative resection, but were found to have lymph node metastasis, patients treated with peptide vaccine showed a significantly higher 5-year esophageal cancer-specific survival rate than the non-vaccinated group (60.0% vs 32.4%, P = 0.045); the difference was more significant in patients with tumors without CD8+ or PD-L1 expression (68.0% vs 17.7%, P = 0.010)76. This evidence concerns the gene CD8A and esophageal cancer.