HLA-C and neoplasm: Additionally, since the proteogenomic search was not restricted to ncORFs from tumor specific transcripts, we also considered nine epitopes (MHC-bound peptides) from ncORFs in lowly expressed genes in normal tissue from GTEx (median expression across samples: <1 transcript per million) in the same tissue in which the peptide is identified as a more accurate subset of MHC-bound peptides, yielding a total of 18 MHC-bound peptides supported by at least one of these filters (i.e. low retention time error and low expression in GTEx tissues).