Frequent expression of soluble Fas and Fas ligand in Chinese stomach cancer and its preneoplastic lesions

To investigate the frequency and pattern of Fas and Fast expression in the gastric mucosa at different stages of gastrocarcinogenesis, the combined ex aminations of pathology, immunocytochemistry and Western blot hybridisation were performed on the cancer specimens as well as their preneoplastic and non-cancerous counterparts. The frequencies of Fas and Fast expression were found to be 6.3% (1/16) and 62.5% (10/16) in non-cancerous mucosa, 60% (6/ 10) and 80% (8/10) in atrophic gastritis, 75% (9/12) and 83% (10/12) in int estinal metaplasia, 100% in both dysplasia Grades II (20/20) and Grade III (15/15) and 4 types of gastric carcinomas (74/74). Two forms of Fast protei n in 37 kDa and 26 kDa were detected in all FasL(+) cases. Soluble Fas (30 kDa) but not the membrane-type (43 kDa) is predominantly expressed in the F as' cases. Our data thus suggest a close correlation of soluble Fas with st omach tumour progression P<0.01. The sFas protein, together with the tumor- derived soluble and membrane Fast, may confer on the transforming and trans formed gastric epithelial cells an immune advantage enabling escape from en dogenous and exogenous suicide signal(s).