Expression of pS2 (an estrogen-induced gene isolated from breast carcinoma MCF7 cells) and of the human spasmolytic peptide (hSP) gene was analyzed in 21 human biliary tract and gallbladder carcinomas and 16 non-neoplastic gallbladders at the protein level (immunochemistry) and, in a series of these cases, at the RNA level (Northern blots). Eighteen carcinomas and 14 non-neoplastic mucosae with inflammatory alterations showed pS2 activity by immunostaining or Northern blotting. In addition, in samples with pS2 expression, hSP RNA was demonstrated. In the corresponding non-neoplastic and healthy mucosae, pS2 was negative, as judged by immunostaining. Northern blots showed weak (basal) level of activity for pS2 and hSP. The genes' increased expression in correlation to inflammatory and neoplastic processes, by now observed in several carcinomas and idiopathic inflammatory bowel disease, hints to their essential role in such diseases.