The study is aimed to the test efficacy and safety of neoantigen-primed dendritic cell (DC) cell vaccine therapy for postoperative locally advanced gastric cancer, hepatocellular carcinoma, lung cancer and colorectal cancer, and to explore the biomarkers related to efficacy and adverse event.

Postoperative patients with pathological confirmed locally advanced gastric cancer, hepatocellular carcinoma, non-small cell lung cancer and colorectal cancer with standard adjuvant treatment are enrolled. This is a prospective exploratory trial. Patients' tumor tissues are subsequent to whole exosome sequencing and possible neoantigens are identified. DC is in vitro primed with synthesized peptides. Both adverse events and responses are recorded.

Inclusion Criteria:

• Participants with a first diagnosis of gastric cancer, hepatocellular carcinoma, non-small cell lung cancer, colorectal cancer who have undergone a curative resection or ablation
• Anticipated life time > 3month
• Eastern Cooperative Oncology Group (ECOG) performance status (PS) 0 or 1
• Adequate organ functions

Exclusion Criteria:

• Any evidence of tumor metastasis or co-existing malignant disease
• Tumor emergency
• Abnormal coagulation condition
• Contagious diseases, such as hepatitis B virus, hepatitis C virus, human immunodefficiency virus, tuberculosis infection
• Concomitant tumors
• Immunological co-morbidities