AdenoCA of Colon : Carcinoembryonic Antigen
Carcinoembryonic antigen (CEA) is a family of highly related cell surface-anchored glycoproteins that are involved in cell adhesion and secreted in the gastrointestinal tract during embryogenesis. The CEA synthesis stops at birth and only low levels are detected in normal adults. CEA levels are elevated in many cancers, including colorectal carcinoma (70-100% of patients), stomach, pancreas, thyroid (medullary), breast, lung, and prostate cancers. In colorectal carcinoma, higher levels are associated with high-grade tumors, tumor extension outside the bowel wall, and the presence of vascular and perineural invasion. The levels drop after the resection of the tumor and are used to monitor for early recurrences or metastases. In the absence of malignancy, CEA levels may be elevated in individuals with cirrhosis, inflammatory bowel disease, pancreatitis, and heavy smokers. CEA blood test is not reliable as a screening test or for early diagnosis of colorectal cancer. Reference range in non-smoker adults is 0-3 ng/ml. The image shows a slice through adenocarcinoma of colon. Normal large bowel mucosa can be seen on the either side of the polypoid tumor.