A perturbation of the cytokine network characterised by low levels of IL-12 and normal or high levels of IL-10 has been previously reported in patients with neoplasms of various organs (O'Hara et al, 1998; Jacobs et al, 1998; Merendino et al, 1999); it has been suggested that this imbalance in IL-12 and IL-10 levels could explain the shift from type 1 to type 2 cytokine production by T lymphocytes known to occur in cancer patients (Elässer-Beile et al, 1993; Clerici et al, 1994; Clerici et al, 1997, 1998). The gene discussed is IL10; the disease is cancer.