Following the demonstration that IL-2 could achieve responses in a small number of patients with malignant melanoma, this group subsequently developed techniques to expand tumour-infiltrating lymphocytes (TIL) in vitro. When TIL were infused into patients, a modest improvement in response rate became apparent, although success was hampered by poor in vivo persistence of transferred cells (Rosenberg et al, 1994). The gene discussed is IL2; the disease is neoplasm.