For activation and maintenance of tumour-infiltrating CD8+ T cells, CD4+ T cells play an important role by secreting cytokines such as interleukin-2, which is required for CD8+ T-cell growth and proliferation (Rosenberg et al, 1988, 1998; Yoshino et al, 1992; Cheng et al, 1998; Wang and Rosenberg, 1999; Rosenberg, 2001; Wang, 2001; Zeng, 2001). The gene discussed is CD4; the disease is neoplasm.