Immunohistochemical study was performed on expressions of c-myc, c-fos and CA19-9 in gallbladder tissue with or without malignant lesions. A total of 81 tissues were divided into four groups including 47 carcinomas, 3 dysplasias, 17 metaplasias and 14 normal lesions. After these tissues were routinely fixed in 10% formalin solution and embedded in paraffin, 4 micrometer-thick sections were made and stained with hematoxylin-eosin to classify the type of lesions. Immunohistochemical stains were carried out for c-myc and c-fos oncoproteins, and CA19-9. The percentages of positive reaction for c-myc oncoprotein were 77%, 67%, 88% and 36%, those for c-fos oncoprotein were 83%, 66%, 35% and 7%, and those for CA19-9 were 85%, 100%, 88% and 71% in carcinoma, dysplasia, metaplasia and normal tissues, respectively. These results suggest that c-myc and c-fos oncogenes play some kind of roles in malignant transformation of the gallbladder tissues and that abnormal expression of CA19-9 is the sign of antigen reversion of carcinoma cells toward embryonic cells of the gallbladder tissue
