Using immunohistochemical and Northern blot hybridization techniques, the expression of epidermal growth factor (EGF) and its mRNA was studied in 3 human pancreatic carcinoma cell lines and their in vivo tumor lines. 2 out of 3 cell lines (PC-2 and PC-3) showed strong immunoreaction with EGF antiserum whereas PC-1 was stained weakly. Northern blot exhibited expression of EGF mRNA in PC-2 and PC-3. No EGF mRNA was detected in PC-1. The detectable levels of EGF protein and EGF mRNA in this study and EGF receptor mRNA in our previous study, indicated the presence of autocrine cycle in human pancreatic carcinoma cell lines. The autostimulation of growth factor to cancer cells and overexpression of growth factor receptors may be the main mechanism of uncontrolled growth of cancer cells.