Decreased expression of Fas (CD95/APO1) associated with goblet cell metaplasia in Barrett's esophagus.

Fas ligand (FasL) has been shown to induce apoptosis in cells expressing its receptor Fas. We have recently shown that Fas ligand is overexpressed in all cases of Barrett's metaplasia (BM) with dysplasia and esophageal adenocarcinomas, and in a few cases of BM negative with dysplasia. The aim of this work was to determine the status of Fas expression in BM with and without dysplasia or carcinoma. Formalin-fixed and paraffin-embedded tissue sections from esophageal biopsies and esophagectomy specimens with BM, with and without dysplasia and carcinoma, were immunostained for Fas and FasL using the immunoperoxidase technique. The percentage of positive cells in each case was evaluated and compared with the degree of dysplasia. When Fas expression was assessed in glands with goblet cell metaplasia, Fas immunoreactivity was either undetected or present in less than 10% of the cells in 85% of the cases, and only 1 (4%) of the 28 cases examined showed Fas immunoreactivity in more than 25% of the cells. When we compared Fas expression in goblet cell-containing glands with glands of gastric cardia phenotype, we found that in the 26 cases of BM with or without dysplasia Fas was completely undetectable in goblet cell-containing glands in 15 (58%) of the cases but was undetectable in only 3 (12%) of the glands with gastric cardia phenotype (P = .002). Fas is usually undetectable or is expressed at a low level in BM with or without dysplasia or carcinoma. Fas expression in goblet cell-containing glands is less frequent than in glands with gastric cardia phenotype in the same specimens. BM with dysplasia or carcinoma overexpress FasL, so decreased Fas expression may protect BM with dysplasia and carcinoma from self-destruction while allowing them to evade immune surveillance.