Characterization of colon cancer–associated antigens that would be key therapeutic targets in the prevention of disease relapse or progression.

594 Background: Colon cancer (CRC) is an immunogenic tumor and adaptive immunity may play a role in inhibiting disease relapse. A vaccine to boost cellular immunity in CRC patients could prevent disease recurrence, but there have been few defined immunogenic proteins identified as vaccine candidates. TVG has shown that overexpressed tumor associated proteins, abundant in the cancer state but expressed at basal levels in normal cells, can be immunogenic. We hypothesized that ideal candidate antigens would be ones already validated as prognostic markers in multivariate analysis. Methods: From a directed literature review we selected antigens based on (1) incidence of expression, (2) independent predictor of poor prognosis or early disease recurrence, and (3) known biologic function in CRC pathogenesis. We identified peptides that were predicted to be high affinity binders across multiple HLA DR alleles. We evaluated immunogenicity of peptides with IFN-g ELISPOT assays in CRC and control patients. We then ev...