HCT-116 cells were treated either with 5 µM of the NMD inhibitor 5-azacytidine (PMID: 25319547) or DMSO (negative solvent control) for 24 h to examine differences in HLA class I-mediated peptide presentation. Moreover, data were used for the identification of tumor-specific neoepitopes originating from insertion/deletion mutations due to microsatellite instability.