A case of early cancer in the gallbladder: immunohistological analysis with monoclonal antibodies.

A case of early cancer in the gallbladder is reported. The tumor was disclosed as an echogenic nodular lesion with irregular margin by ultrasonography and endoscopic retrograde cholangiography. Among several tumor markers, CA19-9 showed a slightly higher level (51 U/ml). An operation was carried out because of the tumor size (over 10 mm) and the coexistence of a gallstone. The tumor was a well differentiated tubular adenocarcinoma. In the carcinoma tissue, CA19-9 and YH206 antigens showed different staining patterns, the latter antigen being detected by the monoclonal antibody, YH206, established in our laboratory. Although CA19-9 was strongly positive in the non-cancerous gallbladder epithelial cells, the YH206 antigen was negative. A slight elevation of the CA19-9 level in the patient's serum was probably caused by a diffusion of the CA19-9 antigen from the gallbladder epithelial cells to the serum, due to inflammation. On the other hand, it is interesting to note that the YH206 antigen was not demonstrated in the non-cancerous gallbladder epithelial cells but was in the cancer tissue.