We have previously demonstrated that RelA is constitutively activated in the majority of human pancreatic cancers and plays an important role in tumorigenesis and metastasis. The antiapoptotic gene bcl-xl is a downstream target of RelA, and regulation of bcl-xl transcription is mediated directly by the nuclear factor κB (NF-κB) binding sites present in the upstream promoter element of the bcl-xl gene. In this study we investigated the effects of inhibition of epidermal growth factor receptor (EGFR) signaling pathway with the anti-EGFR monoclonal antibody IMC-C225 on constitutive NF-κB activation and regulation of apoptosis-related genes in human pancreatic cancer cells. We found that activation of EGFR can be blocked with the anti-EGFR antibody IMC-C225 in the human pancreatic cancer cell line MDA Panc-28, leading to a marked decrease in constitutive NF-κB DNA binding activity. Our data also suggest that downregulation of NF-κB DNA binding activity by IMC-C225 leads to a decrease in bcl-xl and bfl-1 expression. Therefore, targeting the NF-κB signaling pathway with an anti-EGFR antibody may be one strategy to restore apoptosis in human pancreatic cancer cells, thereby enhancing the effect of chemotherapy and radiation therapy. ( J Gastrointest Surg 2003;7:37-43.)