Heterogeneity of antigenic constellation in human hepatocellular carcinoma

Hepatocellular carcinoma is one of the primary liver malignancies responsible for over a million deaths per year worldwide (approximately 10% of all deaths in the adult age range). The diagnosis of HCC can be difficult and often requires the use of more than one microscopic technique. A retrospective study was performed on a study batch of 42 cases that died of HCC due to metastasis or other secondary complications. Tissue samples were taken in order to investigate the tumour antigenic constellation by means of IHC method using a large variety of antibodies. In situ hybridization was also performed for albumin mRNA to assess the albumin expression in some selected cases. Telomerase activity was investigated using IHC method for the hTERT catalytic subunit. A cocktail of hepatic cytokeratins (CK8, 18) combined with Hep Par-1 and associated to albumin proved to be more powerful than albumin alone in differentiating HCC and increased the value of tumour diagnosis. hTERT expression was proportionally reverse to the tumour degree of differentiation, but was independent from the expression of tumour-proliferating indexes. The heterogeneity of the antigenic constellation in hepatocellular carcinoma suggests an antigenic mosaicism, which can be expressed a synchronous or metachronous manner, depending on the tumour degree of differentiation.