CD8A and neoplasm: However, following initial anecdotal reports of recognition of non-templated peptides generated by proteasome-catalyzed “cut-and-pasting” of non-contiguous fragments of a polypeptideby tumor-specific CD8+ T cells (3–5), increasing evidence has accumulated to support the concept that proteasome-catalyzed peptide splicing (PCPS) reactions comprise an additional source of peptides that can be presented on HLA-I molecules for CD8+ T cell recognition (6–14).