The expression of mRNA for epidermal growth factor (EGF), transforming growth factor-alpha (TGF-alpha), EGF receptor (EGFR) and c-erbB-2 genes and the immunoreactivity to these gene products were examined in 3 newly established human pancreatic carcinoma cell lines and their corresponding in vivo tumor lines using the Northern blot technique and the immunohistochemical method. All 3 cell lines expressed TGF-alpha, EGFR and 2 of the 3 lines expressed EGF and c-erbB-2 mRNAs. The immunohistochemical study showed immunoreactivity to EGF, TGF-alpha and EGFR in all these 3 cell lines and their corresponding in vivo tumor lines. These results indicate that the autocrine loop of EGF and/or TGF-alpha/EGFR in pancreatic carcinoma cells may be one of the important reasons for the uncontrolled growth of the pancreatic carcinoma. The c-erbB-2 overexpression in some of the cell lines may also contribute to the carcinogenesis or progression of this cancer.