ERAP1 and ERAP2 [endoplasmic reticulum aminopeptidase 1 and 2, which form a protein complex (25)], both play a role in peptide trimming for presentation on major histocompatibility complex (MHC) class I, and are both targeted by tosedostat, which is currently in development for the treatment of cancers (fig. This evidence concerns the gene ERAP2 and cancer.