STAP2 and fibrosarcoma: Subcutaneous CMS5a tumor cell (mERK2+ fibrosarcoma line [BALB/c background])-bearing BALB/c mice were infused with STAP2 siRNA- or scrambled siRNA-introduced DUC18 CD8+ T cells, and then subjected to in vitro or in vivo vaccination with mERK2 peptide or mERK2-encoded DNA.