Updated project metadata. This project explored the relationship between ionizing radiation and antigen presentation using both proteomic and immunopeptidomics methodologies. We investigated the radiation-specific changes which occur in the colorectal tumor cell proteome associated with changes in dose and time after irradiation. We used this data to observe the changes in key regulators and effector proteins of the antigen processing and presentation machinery. Furthermore, a parallel immunopeptidomics analysis enabled a peptide-level assessment of antigen presentation to correlate changes observed in the proteome thereby defining a radiation-specific peptide repertoire. A nuanced relationship between protein expression and antigen presentation was observed where radiation-induced changes in proteins do not always correlate with increased presentation of associated peptides. Furthermore, a neoantigen which increases in the context of radiation was characterised. This study provides new insights into how radiation enhances antigen processing and presentation that could be suitable for the development of combinatorial therapies.