Histogenetical investigations on adenocarcinomas of the esophagogastric junction. An immunohistochemical study.

The presence of Pepsinogen II (PG II), gastral mucin (2B5), CA 19-9, BW 494 and Cytokeratin 20 (CK 20) was investigated in 69 adenocarcinomas of the esophagogastric junction (15 carcinomas in Barrett's esophagus, 9 distal esophageal carcinomas, 31 carcinomas of the cardia and 14 subcardial carcinomas). Evidence of gastric differentiation (expression of Pepsinogen II and/or gastric mucin) was found in more than 50% of the Barrett's carcinomas and the carcinomas of the cardia, but only in 20% of the subcardial carcinomas. High rates of antigen expression were found for the "intestinal" markers CA 19-9 (between 55.5% and 100%) and BW 494 (between 42.9 and 86.7%). CK-20 expression was detected to a significantly higher degree in Barrett's carcinomas (73.3%) than in the other groups (between 29% and 44.4%). These data indicate that the distribution of adenocarcinomas with gastric and/or intestinal differentiation at the esophagogastric junction forms a continuum without clear-cut borders.