After recognizing a malignant antigen, a cluster of differentiated (CD)4+ T helper (Th) cells can secrete pro-inflammatory cytokines to recruit additional immune cells and mount an immune response, whereas CD8+ cytotoxic T lymphocytes (CTL) can directly destroy tumor cells by secretion of cytotoxic molecules such as granzymes leading to apoptosis [9]. The gene discussed is CD4; the disease is neoplasm.