In this study, we sought to identify naturally presented MHC peptides in 8 human cancer cell lines: PANC.1, A.375, SW527, CaSki, PC.3, LNCaP_clone_FGC, MCF.7, and VMRC.LCD. Peptides identified were 8-15 amino acid long with the majority between 8 to 11 amino acids which match known properties of MHC-I presented peptides. Number of identifications differs between cell lines and ranges between 1834-5425 peptides.