ABSTRACT
The localization of the carcinoembryonic antigen (CEA) in carcinomas and mucosae of the digestive tract in humans and in mesenteric lymph nodes was studied by indirect immunofluorescence. In colonic and gastric adenocarcinomas, CEA had typical centroglandular localization. Cytoplasmic localization of the CEA was seen in invasive cancer cells having lost their glandular organization. CEA was also present in colonic and gastric mucosae surrounding the tumor. In gastric mucosa obtained at autopsy from subjects with nonneoplastic diseases, CEA was found only in glands having undergone intestinal metaplasia. In lymph nodes of cancer patients CEA was always present in metastatic cells and in germinal centers. Characteristic localization of CEA in germinal centers of metastatic and nonmetastatic lymph nodes could suggest the presence of CEA-anti-CEA immune complexes.