Human pancreatic cancers over‐express the epidermal growth factor receptor (EGF‐R) and all 5 known ligands of the EGF family, including EGF, transforming growth factor‐alpha (TGF‐α), amphiregulin, betacellulin and heparin‐binding EGF‐like growth factor (HB‐EGF). The aim of the present study was to confirm the presence of EGF‐R‐dependent autocrine loops in a human pancreatic cancer cell line and to explore the possibility that interrupting EGF‐R activation by introducing a truncated receptor abrogates pancreatic cancer cell growth. The anchorage‐independent growth of PANC‐1 human pancreatic cancer cells, previously shown to express TGF‐α, was inhibited by specific anti TGF‐α antibodies. PANC‐ 1 cells were then either transfected with an expression plasmid encoding a kinase‐deficient EGF‐R cDNA (HER653) or infected with the same EGF‐R cDNA using a retroviral vector. Multiple transfected and infected clones co‐expressed the truncated EGF‐R and endogenous EGF‐R as revealed by Northern blot analysis and immunoblots. In these clones, there was a marked attenuation in EGF‐ and TGF‐α‐mediated EGF‐R tyrosine phosphorylation and c‐tos induction. There was also a significant decrease in colony formation in soft agar by comparison with control cells and a significant increase in the effect of the growth‐inhibitory effect of the alkylating agent cisplatinum in these clones. Our observations indicate that dominant negative inhibition of EGF‐R may have therapeutic potential in pancreatic cancer. © 1996 Wiley‐Liss, Inc.