Identification of Shared Neoantigens in -Related Breast Cancer.

Personalized neoantigen-based cancer vaccines have been shown to be safe and immunogenic in cancer patients; however, the manufacturing process can be costly and bring about delays in treatment. Using off-the-shelf cancer vaccines targeting shared neoantigens may circumvent these problems. Unique mutational signatures and similar phenotypes found among -mutated breast cancer make it an ideal candidate for discovering shared neoantigens within the group. We obtained genome sequencing data of breast cancer samples with or without somatic mutations (-positive and -negative, respectively) from the three public cancer databases; The Cancer Genome Atlas (TCGA), International Cancer Genome Consortium (ICGC), and Catalogue of Somatic Mutations in Cancer (COSMIC); and from three studies with whole genome/exome sequencing data of samples with germline mutations. Data were analyzed separately within the same database/cohort. We found H1047R, E545K, E542K, and N345K recurrently in -negative groups across all databases, whereas recurrent somatic mutations in -positive groups were discordant among databases. For germline -mutated breast cancer, R175H was unanimously the most frequent mutation among the three germline cohorts. Our study provides lists of potential shared neoantigens among -related breast cancer, which may be used in developing off-the-shelf neoantigen-based vaccines.