We compared morphological, biological and molecular biological patterns of a newly established, spontaneously immortalized pancreatic ductal cell line, TAKA-1, with a hamster pancreatic ductal adenocarcinoma cell line, PC-1. PC-1 cells grew in a monolayer on plastic tissue culture flasks, whereas TAKA-1 cells required type I collagen gel matrix to propagate. The growth rate and argyrophilic nuclear organizer region (Ag-NOR) counts were greater in PC-1 cells than in TAKA-1 cells. More TAKA-1 cells were in G0/G1 and less were in the S cell cycle phase than PC-1 cells. Karyotypically, the consistent change in TAKA-1 cells was an abnormal no. 3 chromosome, whereas additional chromosomal abnormalities were found in PC-1 cells. Ultrastructurally, TAKA-1 cells formed ductal structures and were composed of two types of cells, as in the normal hamster pancreatic ducts, whereas PC-1 cells were pleomorphic, showed evidence for loss of differentiation and contained intracytoplasmic lumens. Unlike the PC-1, TAKA-1 cells did not show a point mutation at codon 12 in the c-Ki-ras oncogene and did not grow in soft agar. Receptor binding assay showed specific epidermal growth factor binding to both cell lines, but secretin binding only to TAKA-1 cells. Both cells produced and released transforming growth factor-alpha in serum-free medium. Both cell lines expressed blood group A antigen, carbonic anhydrase, coexpressed cytokeratin and vimentin, and reacted with tomato and Phaseolus vulgaris leucoagglutinin (L-PHA) lectins. The results demonstrate that chromosomal abnormalities, cell cycle patterns, expression of cytokeratin 18, lectin bindings and the c-Ki-ras mutation are the features that distinguish the benign from the malignant pancreatic ductal cells in Syrian hamster.