MHC class II-activated CD4+ T cells mainly release cytokines to recruit and activate more CD4+/CD8+ T cells and B cells, while MHC class I-activated CD8+ T cells can recognize non-self-antigens presented by MHC class I on virus-infected or tumor cells and secrete perforin and granzyme to kill these abnormal cells [1]. This evidence concerns the gene CD8A and neoplasm.