Twenty-nine patients with adenocarcinomas of gastrointestinal or unknown primary, and three with advanced neuroendocrine tumours, were entered into a study of bolus plus infusional 5-fluorouracil (FUra) modulated with high-dose leucovorin (LV) and recombinant interferon alpha 2a (IFN-alpha). Here, IFNA2 is linked to neuroendocrine neoplasm.