Recently, it has been indicated that CD4+ Th cells play a crucial role in tumour immunology in addition to CD8+ CTL in both animal and human systems (Nishimura et al, 1999; Marzo et al, 2000; Ikeda et al, 2004; Janssen et al, 2005; Hunder et al, 2008). The gene discussed is CD4; the disease is neoplasm.