The alteration of Fas receptor and ligand system in hepatocellular carcinomas: how do hepatoma cells escape from the host immune surveillance in vivo?
Hepatology
; 30(2): 413-21, 1999 Aug.
Article
em En
| MEDLINE
| ID: mdl-10421649
ABSTRACT
Escape from the immune surveillance may play an important role in tumor outgrowth and metastasis. Alteration of the Fas receptor (Fas)/ligand (FasL) system including soluble forms is regarded as one of the mechanisms preventing the immune system from rejecting the tumor cells. However, less attention has been paid to the role of Fas/FasL interaction in vivo. Therefore, we investigated the expression of Fas and FasL by immunohistochemistry and reverse-transcription polymerase chain reaction (RT-PCR) and measured the serum levels of soluble Fas (sFas) and FasL (sFasL) in 44 patients with hepatocellular carcinoma (HCC). In the noncancerous liver tissues, Fas expression was up-regulated in most cases, and FasL expression was detected in 6 cases. In Fas-positive HCC cases (n = 15), the intrahepatic metastatic foci was less (P =.037), apoptosis of tumor cells was more (P =.004), the disease-free survival rate was higher (P =.004), and p53-positive cases were less (P =.003), compared with Fas-negative cases. The sFas and sFasL levels in HCC patients were significantly higher and lower than those in controls, respectively. RT-PCR and immunohistochemistry revealed generation of sFas in the hepatocytes and tumor-infiltrating mononuclear cells rather than in hepatoma cells. Accordingly, hepatoma cells may eliminate Fas expression on themselves and let the hepatocytes and infiltrating mononuclear cells generate sFas to escape from the immune system and to produce metastasis. FasL might contribute to malignant transformation in some circumstances, because hepatocytes in the pericancerous pseudolobules expressed FasL.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Glicoproteínas de Membrana
/
Carcinoma Hepatocelular
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Receptor fas
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Neoplasias Hepáticas
Tipo de estudo:
Screening_studies
Limite:
Adult
/
Aged
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Female
/
Humans
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Male
/
Middle aged
Idioma:
En
Revista:
Hepatology
Ano de publicação:
1999
Tipo de documento:
Article
País de afiliação:
Japão