Origin of intraepithelial apoptotic cells in human colorectal adenomas

The origin of intraepithelial apoptotic cells in human colorectal adenomas was examined using immunohistochemistry. Tissue sections of human colorectal adenomas obtained during surgery or endoscopy were stained by the streptavidin-biotin method using antibodies against carcinoembryonic antigen (CEA) and leukocyte common antigen (LCA). Approximately 15.7% of apoptotic bodies stained positive for CEA with immunoreactivity on the cytoplasm, whereas all cells stained negative for LCA. These findings suggest that intraepithelial apoptosis in human colorectal adenomas originates from adenoma cells rather than infiltrating lymphocytes as previously proposed, and that apoptotic cells maintained their cytoplasmic antigenicity in the early stages of apoptosis.