Phenotypic characterization of pentamer+ cells using the cytotoxicity marker CD43 [33] revealed that in untreated tumor-bearing mice, both CD43hi and CD43lo pentamer+ tumor specific CD8 T cells were present (Figure 4D), whereas the small populations of pentamer+ CD8 T cells in CY-treated mice appeared to be CD43lo. This evidence concerns the gene CD8A and neoplasm.