['Adjuvant interferon based chemoradiation has rendered promising results against pancreatic cancer. This study evaluated the in vivo effect of interferon α on two human pancreatic carcinoma cell lines implanted in nude.', 'MiaPaCa-2 expressed the interferon α/β receptor and Panc-1 cells did not. Regimen I consisted of intraperitoneal single-agent gemcitabine and Regimen II consisted of IFN-α and gemcitabine biweekly for 30 d.', 'Regimen I and II significantly decreased median tumor volume compared with control mice (P < 0.001). However, MiaPaCa-2 showed a more dramatic response to Regimen II compared with Panc-1 implanted mice. MiaPaCa-2 and treated with Regimen II showed less metastasis and less local invasion compared with Panc-1 treated with same regimen. Regimen II was more effective on MiaPaCa-2 compared with Regimen I (P < 0.001). There were no differences between Regimens I and II in the Panc-1 group.'] Is the expression of interferon receptor α/β in human pancreatic cancer in nude mice essential for tumor response to interferon α treatment?