Albumin gene expression in liver tumors: diagnostic interest in fine needle aspiration biopsies.

Albumin is a specific product of normal and transformed hepatocytes, but unfortunately its immunohistochemical demonstration proves unreliable because of diffusion artifacts. An in situ hybridization procedure to reveal albumin mRNA was applied to fine needle aspiration specimens of liver nodes with the aim of testing the usefulness of this marker in the cytological diagnosis of hepatocellular carcinomas (HCC). A 51-base pair oligonucleotide probe was labeled with digoxigenin and used on paraffin sections of alcohol-fixed cell blocks. A series of 97 cases originally interpreted, on the basis of cytology alone, as "hepatocellular carcinoma" (62 cases), as "carcinoma cells, not otherwise specified" (15 cases), as "adeno-carcinoma" (16 cases), and as "non-epithelial neoplastic cells" (4 cases), was studied. In all cases, clinical and follow-up information was obtained; a diagnosis of HCC was reached with certainty in 44 cases and suspected in 22. Thirty-one other cases were proven to be bile duct adenocarcinomas or metastatic tumors. Taking into account proven cases only, albumin mRNA was found in 42/44 HCC and in none of the control cases (sensitivity, 95.5%; specificity, 100%). Of 22 cytologically suspected HCC, albumin mRNA was positive in 19 cases. Also, high grade pleomorphic HCCs expressed albumin gene, and this finding is of value in the differential diagnosis with liver metastases of anaplastic tumors from lung, adrenal, pancreas, etc. The diagnosis of HCC on a cytological basis is becoming increasingly important because most cases are unresectable and have to be included in different therapeutic protocols.(ABSTRACT TRUNCATED AT 250 WORDS)