Immunobiology and gene-based immunotherapy of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the major malignancies worldwide. For most patients with advanced or multifocal HCC treatment options are limited resulting in a poor prognosis. Several local ablation methods have been developed as minimally invasive strategies for HCC treatment. It is unclear, until now, whether these therapies will significantly improve the poor prognosis of patients with unresectable HCC. Novel therapeutic strategies and a better understanding of HCC imunobiology are, therefore, urgently required.

The scientific literature since 1970 in all languages cited in Medline was systematically reviewed.

Until now, a variety of specific and non-specific immunostimulatory strategies against HCC has been applied in preclinical experimental models with some promising results. The molecular characterization of HCC associated tumour antigens such as alpha-fetoprotein (AFP) and the increased understanding of the immunological pathways involved in liver and tumor immunology have paved the way for the design of promising gene-based cancer vaccines. The first phase I and II immunotherapeutic clinical trials based on dendritic cell immunotherapy and peptide vaccines are ongoing in HCC-patients. Clinical trials have, in general, demonstrated the safety of such strategies. Recently, exciting new immunological techniques and tools have been developed which allow to characterize antigen specific T cells at a single-cell level. In future, HCC specific tumor rejection antigens which can be used therapeutically have to be identified using microarray-based analysis. The different therapeutic modalities need to be compared directly resulting in optimised therapeutic approaches and the identification of sub-groups of HCC-patients responding favourably to treatment.