Disclosed herein is a system and methods for determining the alleles, neoantigens, and vaccine composition as determined on the basis of an individual's tumor mutations. Also disclosed are systems and methods for obtaining high quality sequencing data from a tumor. Further, described herein are systems and methods for identifying somatic changes in polymorphic genome data. Further, described herein are systems and methods for selecting a subset of patients for treatment. A utility score indicating an estimated number of neoantigens presented on the surface of tumor cells is determined for each patient based on one or more neoantigen candidates identified for the patient. The subset of patients are selected based on the determined utility scores. The selected subset of patients can receive treatment, such as neoantigen vaccines or checkpoint inhibitor therapy. Finally, described herein are unique cancer vaccines.