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Definition of tumor-associated antigens in hepatocellular carcinoma
F Stenner-Liewen1, G Luo, U Sahin
1University of the Saarland, Medizinische Klinik I, Homburg/Saar, Germany. stenlie@burnham-institute.org
Insights
Researchers identified 19 tumor antigens in hepatocellular carcinoma (HCC) patients using SEREX. These antigens, many liver-linked, show promise for understanding HCC immune responses and developing new therapies.
Area of Science:
- Immunology
- Oncology
- Hepatology
Background:
- Hepatocellular carcinoma (HCC) is a prevalent global cancer with high mortality, particularly in Africa and Asia.
- Current understanding of HCC pathogenesis and treatments for inoperable cases remain limited.
- Identifying tumor antigens is crucial for developing targeted immunotherapies.
Purpose of the Study:
- To identify novel tumor antigens in hepatocellular carcinoma (HCC) through immune response analysis.
- To investigate the humoral immune response in HCC patients.
- To explore potential targets for HCC gene therapy.
Main Methods:
- Screening of a human HCC cDNA library using the SEREX (SERum EXpression) approach with autologous IgG.
- Identification and sequence analysis of cDNA clones reactive with autologous antibodies.
- Frequency analysis of antibody responses using a panel of allogeneic sera from various patient groups and healthy individuals.
Main Results:
- Nineteen distinct antigens reactive with autologous IgG were identified.
- Three novel proteins and 16 known gene products (including LDH, albumin, kinectin, and transcription/translation factors) were identified.
- A high percentage of HCC patient sera recognized these antigens, while control sera showed rare reactivity, indicating specificity.
Conclusions:
- The study reveals the complexity of the humoral immune response in hepatocellular carcinoma (HCC).
- Identified antigens, many associated with liver function, represent potential targets for HCC diagnostics and therapeutics.
- Findings offer new insights into the molecular mechanisms of liver cell transformation in HCC.
Abstract:
With an estimated annual incidence of about one million cases, hepatocellular carcinoma (HCC) is one of the most common neoplasms worldwide. Of all malignant diseases, it is the major cause of death in some regions of Africa and Asia. The pathogenic mechanisms responsible for HCC are not well defined, and therapeutic means, especially in inoperable HCCs, are still unsatisfactory and await improvement. In the quest for tumor antigens exploitable for gene therapy, we studied immune responses in the context of HCC. A cDNA library derived from a human HCC sample was screened using the SEREX approach. Nineteen distinct antigens reactive with autologous IgG were identified. Sequence analysis revealed three of the cDNA clones to code for hitherto unknown proteins and 16 known genes products. Proteins as diverse in function as LDH, albumin, and kinectin were found. Furthermore, proteins involved in the transcription/translation machinery had elicited an immune response in the autologous host. A panel of allogenic sera including sera from patients with hepatitis, liver cirrhosis, HCC, and other tumor entities, as well as sera from normal individuals, was used for frequency analysis of antibody responses. Whereas allogenic sera of HCC patients detected most antigens at a high percentage, control sera were rarely antibody-positive. The nature of the major fraction of antigens described here are linked to liver. Thus, our findings demonstrate not only the complexity of the humoral immune response against HCC, but may also offer new insight into mechanisms underlying transformation of the liver cell.