HEP-PAR-1 AND SELECTED ANTIBODIES IN THE IMMUNOHISTOLOGICAL DISTINCTION OF HEPATOCELLULAR-CARCINOMA FROM CHOLANGIOCARCINOMA, COMBINED TUMORS AND METASTATIC CARCINOMA

Aims: To examine the usefulness of Hep Par 1 together with selected an tibodies in the separation of hepatocellular carcinoma (HCC) from chol angiocarcinoma (CC), combined tumours (HCC-CC) and metastatic carcinom a. Methods and results: Antibodies to Hep Par 1, CK19, CK20 and factor XIIIa were applied to 32 HCCs, 27 CCs, five HCC-CCs and 19 metastatic carcinomas from a variety of sites. Hep Par 1 produced distinctive gr anular staining of all benign hepatocytes and stained 30 HCCs in a het erogeneous manner, irrespective of the degree of differentiation. Whil e labelling all cases of combined HCC-CC, the antibody also stained th e mucus-secreting cells of four cases of pure CC. Anti-CK19 produced d istinctive staining of bile ducts and CC but also decorated four HCCs and 10 metastatic tumours. Factor XIIIa was not found in normal, react ive or neoplastic hepatocytes. CK20 was found in some cases of HCC and CC and in all cases of metastatic carcinomas from the colon. Conclusi ons: Hep Par 1 was a sensitive marker of hepatocytes but its variable staining in HCC may produce false negative results in small biopsies a nd it was occasionally found in CC. The highest diagnostic yield was o btained when anti-Hep Par 1, CK19 and CK20 were used in a panel. Facto r XIIIa staining has no role in the diagnosis of liver cancers.