The prognostic significance of overexpression of the decoy receptor for Fas ligand (DcR3) in patients with gastric carcinomas.

Background: The FasL-Fas system has an important role in mediating immune-cytotoxic killing of cells such as virus-infected or tumor cells. It was recently reported that there is a soluble decoy receptor (DcR3), which binds to FasL and inhibits FasL-induced apoptosis, and certain tumors may escape FasL-dependent immune-cytotoxic attack by expressing a decoy receptor that blocks FasL. We evaluated whether DcR3 has clinical relevance in actual human gastric cancers.

Methods: : The expression of DcR3 was investigated by Northern blot analysis in a series of 84 primary gastric carcinomas and compared with clinicopathological features and prognosis. The DcR3 expression level was analyzed and quantified densitometrically. The location of DcR3 mRNA in gastric carcinoma tissue was detected by in situ hybridization.

Results: The frequency of DcR3 overexpression was 26% (22 of 84 surgical specimens). The DcR3 expression level was significantly associated with lymph node metastasis and pathological stage, but did not correlate with tumor size, metastatic status, or histological type. In situ hybridization demonstrated that DcR3 mRNA was expressed in tumor cells. When the patients were followed up for 63 months, DcR3 overexpression was found to be associated with a significantly shortened duration of overall survival compared with findings in patients having normal DcR3 expression.

Conclusion: The DcR3 decoy receptor for FasL may be involved in the progression of gastric cancer. Further evaluation of these possible roles of DcR3 and the regulation of DcR3 expression in malignant cells will be critically important for the development of new strategies for controlling the growth of malignant cells that escape host immune surveillance.