A peptide-based, personalized cancer vaccine consisting of patient-specific mutated long peptides, which are immunogenic and unique to the patient's tumor, with potential immunomodulating and antineoplastic activities. Upon vaccination with the personalized neoantigen peptide vaccine iNeo-Vac-P01, the peptides stimulate the host immune system to mount a specific and potent cytotoxic T-lymphocyte (CTL) response against tumor cells expressing the neoantigens, which results in tumor cell lysis.