Recent development in cytokine and growth factor research has demonstrated that the production of cytokines or growth factors by cancer cells induces typical humoral syndromes in patients with various types of neoplasms. Thus, ectopic cytokine syndrome is now an important component of ectopic humoral syndromes. Two conditions ΓÇô granulocytosis syndrome and polycythaemia syndrome ΓÇô are now well characterised. Two other possible entities, tumour hypoglycaemia syndrome and cancer cachexia syndrome, are clinically well recognised, but which factor (or factors) is responsible for these syndromes is not established; candidates are cytokines or growth factors.